ectopic or not

My wife and I are a little confused. We found out she was pregnant last week, she had abdominal soreness and was bleeding. This lasted for around three days. Our Doctor did a pregnancy test on Monday 15th October and it was positive. She requested we go to emergency to have bloods and a scan taken. Bloods were HCG 669 but no scan was taken, (too late in the day). Three days after, (18th Oct) they were HCG 909. By this time there was no bleeding and the pain had decreased a lot.
The following Monday, (22nd Oct) we had another blood test, it was 2408 HCG. Two days after we had a scan which indicated the falopian tube was thickened but they could not say why. They suggested it was an Ectopic Pregnancy and that my wife was six weeks pregnant, however, they could not see anything on the scan. She was advised to go to Emergency and the treating Doctor was confused when she told him the first day of her last period (30th Sept). He stated you would only be around three weeks pregnant and if your dates were correct then we could not pick anything up on a scan. We agreed with this and thanked him for listening because this is what we thought, that the pregnancy was only in its early stage's. Late the same night another Doctor stated we were having an Ectopic Pregnancy because her bloods were 1950 HCG which had fallen from 2408. She spent over night in the Hospital and the next morning another Doctor told her what he was going to do as far as terminating the pregnancy. Once again we advised this Doctor that her cycle's were normal and her dates were correct. We convinced this Doctor to consult with other professionals and they agreed that it may be an early pregnancy, within two to three weeks if we were correct on her cycle dates. Our calculation see's us around three weeks pregnant. We know ovulation to be around the 11th, 12th or 13th of October, she stated feeling soreness in the abdomin on the 14th and 15th of October with bleeding.

We found out within two weeks of trying for our first child and we feel this to be the same, obviously we cannot rule out an Ectopic Pregnancy, however, we have been able to provide the Doctors with another senario.

Is there anyone out there who may be able to give some advice or offer their experience.

Shane, (Hubby)