I've had bleeding on & off with this pg too.
I have had several m/c's as well, so I was terrified as I have never bled with my normal pg's. At the beginning the dr's just said it was the placenta settling in, but it continued on & off till around 7 weeks, & then started again at 16 weeks, which was a worry as it was the placenta coming away. But we're still going strong.