A guy at work told me how someone he plays social netball with had her period THE whole way through her pregnancy, had no idea and was still playing netball at 8 months pregnant - she just thought she'd put on weight! How is that for insane??
The baby was born a little early (like 34-36 weeks?) and quite small, but is fully healthy now.
Just to put your mind at ease.....
I only had an implantation bleed - had no idea what that even was at the time (only when I got back from holiday and read up on it) and because I was in a different time zone, and still had all the period cramping, was sure I was only just hanging on to the pregnancy! I thought I'd get my period any second - specially after the small bleed.
HTH and good luck!!
Fi