Anyone had a BFP after AF??

Hi, My husband and I have been ttc for a few months now and last month I was unwell with a uti and the doctor prescribed amoxycillin. Anyway, for whatever reason I ovulated late at around day 20 (typically I OV around day 12/13) and so we BDd thinking we'd probably missed it anyway. So the tww comes around and I tested and BFN and a couple of days later my period started really really light with brown and then progressed into full on red. It lasted about 5 days and had all the characteristics of a normal period. Anyway, it's CD 7 today and so I started testing with OV sticks. I got a strong positive and was really confused, so I took a pregnancy test and it came up positive straight away, took another and another and all positive, took a clear blue digital and it said pregnant, 1-2 weeks. Managed to get a doctors appointment and he was a bit cautious- he's sent off for blood tests and said i may have just been looking for it and it might not have been anything.Can anyone shed some light on this? I know I have to wait, but I'd really appreciate some opinions! Thanks Xxx