Is it possible that pregnancy could be detected REALLY early...?

I recently miscarried ( a month ago). We have been trying for a really long time and so when my midwife told me was okay, we did. So I had a follow up trans l ultra sound which indicated a thicken endometrium lining (11.5 mm) and increased uterine blood flow. This took place three days after . Now I am not trying to get my hopes up, but both the OBGYN and the Midwife were a little perplexed by all of this. I guess I am wondering if anyone would be able to tell me if the thickening of the lining and increased blood flow may be an EXTREMELY early indication that there may be a fertilized egg.