The first time I had postnatal depression, it crept up on me, insidiously, after two months. I was distracted by the euphoria of first-time motherhood; the late spring was brighter than before, the early blousy roses in bloom as I dandled my new baby in the garden and sang to her.
I didn't see the bindweed edging closer, its tendrils closing around me, paralysing me, stealing my light, choking me until I was powerless. Numb. Empty.
Morbidly depressed, I watched my baby sleeping in her Moses basket and, aged 36, planned my own funeral, agonising over the hymns and deciding that Jerusalem (such a lovely melody) would lift the mood. Assuming anyone turned up.
I quietly stopped eating, stopped feeding the dog. We were both destined to die. I just knew it. My bewildered husband stepped in to look after the dog. I handed him a list of women he should consider marrying after I was gone; they would, I said in all seriousness, make good stepmothers. Not bad ones.
I felt terrible, corroded by poison. To friends and family I perpetrated a daily deceit; I'm just a bit tired. Babies, huh? But yes, so great to lose the pregnancy weight - and more.
But I had been reduced to little more than a high-functioning zombie. So when Adele spoke this week about her awful postnatal depression, I felt a jolt in my solar plexus. As she voiced her fear of having a second child and opening up herself - her whole family - to the potential onslaught of those demons again, I was engulfed in memories dark as Hades.
The 28-year-old singer, whose son, Angelo, is now four, was as unflinching and unsentimental in her words as she is in her lyrics. She recounted the toxic amalgam of obsession and abhorrence, fear, love and inadequacy at the heart of what is a devastating illness. And I understood.
I took pills, she did not. Yet both of us suffered the double bind of fear and guilt; needing to be away from the baby, but terrified that a desperately needed half-hour coffee with girlfriends constitutes a selfish act of betrayal. That's the thing about postnatal depression; it robs you not just of joy but of perspective. I told nobody that as soon as I saw my baby I felt agonising back pain as my muscles contracted in tension.
Having endured a terrifying, bungled NHS birth, it started to prey on my mind. I began ruminating, the flashbacks increased. By the time I sought medical help for my insomnia I had developed post-traumatic stress on top of my postnatal depression.
I was prescribed anti-depressants that sort of worked. Thanks to private healthcare from my then employer, I received psychotherapy from The Priory. I felt better. But I was not better. I might have got better had I not come off the pills after a year in order to have IVF.
Unlike Adele, I wanted another baby regardless. She has talked of the agonising dissonance; how her womb "aches" for a second child, yet the malign spectre of postnatal depression holds her back.
I know two women who never had more children for that selfsame reason; do they regret it? I would never dream of asking. They never say.
Within two days of my elder daughter being born, I knew, in the haze of milky bliss, that I had to have a second. Even in the ensuing nightmare, I never once wavered. Why? Because I stubbornly refused to believe anything as bad could happen to me again.
It took six years of IVF and a series of tiny tragedies - lost heartbeats, miscarriages and the near collapse of my marriage - before I was pregnant again. Did I mention that the depression was so profound, I didn't sleep with my husband for three years? Against that backdrop, the risk of recurring postnatal depression didn't even figure.
One in seven new mothers - 90,000 women - suffers from depression, to varying degrees. Progress has been slow in pinpointing the cause, but a breakthrough was made in 2013 when a study of 200 pregnant women, published in the Journal of Psychiatric Research, found two molecular "signatures" in some individuals' genes that increased the risk of postnatal depression by up to five times.
Researchers believe that changes in oestrogen levels make pregnant women more sensitive to the stress hormone cortisol, and those with the genetic variations are unable to correct the hormonal imbalance after giving birth. My husband later told me he was concerned for my mental health, but I had such a happy pregnancy, he was loath to upset me.
I'd love to say that it was different with my second baby. It was worse. Differently awful. I had another lengthy, ghastly, mismanaged birth and the depression was instant. By the time I was wheeled back to the ward I felt so alienated, so empty, that I literally couldn't bear to look at my new baby. I wince to recall my response to the woman in the bed opposite, cooing and gazing at her new infant with a stupid soppy expression on her face. Mocking me. I felt an irrational hatred for her obvious overacting.
Meanwhile, my daughter had failed to feed or even wake up and was taken off to the special care unit. My days were spent pumping breast milk or crying. The nurses would quietly close the curtains round me as I was upsetting the real mothers.
I thanked God when she recovered and was discharged after a week, but even as I cradled her, I felt a complete fraud. I was horribly aware, with self-flagellating disgust, that I was nothing more than a fake - and panicking in case anyone found out.
As well-wishers came, I mustered the requisite smiles that petered out long before they reached my eyes. They said my baby was beautiful. I knew they were lying. But I dutifully nodded and felt - nothing.
Nothing apart from a sense of horror; that I was a complete monster. Surely only a monster could be so incapable of loving this tiny person whom she had brought into the world? Appalled that I might psychologically damage her, when I changed her nappy I would fix my eyes on the middle distance and bare my teeth in an obscene caricature of a smile. I felt overwhelmed, sad, despairing and ashamed. As far as the world was concerned, I had finally achieved my happy ever after. How could I admit it wasn't good enough; that I wasn't good enough?
Once, I picked her up and went to a neighbour's house. When she opened the door, I thrust the baby into her arms, turned on my heel and left her there. I lay on the sitting room floor listening to the sound of distraught wailing, two doors along, until I couldn't be sure if the screaming was coming from her or me.
I went to my GP. A new anti-depressant and NHS psychotherapy which was good but didn't last long enough. The drugs were good, though; I had no idea how good until months later when I broke my back in a riding accident. I was lucky. I survived. I wasn't crippled. But during the long months of recuperation, I was unable to hold my daughter who was only 10 months when our bond was severed again. I had no upper body strength; I couldn't lift her and when she was placed in my arms she would hit her head against the metal of my back brace, crumple, cry and squirm away, reaching for the nanny as though she were the mother and I the interloper.
Because that is the trick postnatal depression plays; it is a malevolent form of imposter syndrome. You are useless and worthless and in charge of a baby who deserves better.
I'm recovered now. I keep taking the pills because I know I am vulnerable to depression and they maintain my equilibrium. Of course there are days when I feel like a lousy mother, but it's normal-lousy.
Despite my experience I have no regrets. I would do it all again if I had to, in order to be a mother, but I can understand why someone else wouldn't. I adore my daughters, now aged 14 and eight, who have completed me in a way I never imagined possible. But I wouldn't dream of offering Adele advice, because I know how unbearably lonely and tough postnatal depression can be.
All I can say is that after the Stygian gloom, the hellish bleakness, I am able to once more live in glorious technicolour. And I feel utterly blessed.
The Telegraph, London