With my current pgcy hun, I bleed for a few days around the time of AF being due. I thought I was losing this bub and even told my DH that I thought this bub was lost. Ended up all ok for me thank goodness. With my pgcy with V, I bled on and off for a few weeks and thought the same, that one turned out to be a sub chorionic heamotoma which eventually resolved. I had a sub chorionic heamotoma with my previous two pgcy's as well, with brown spotting that lasted quite a while. Im not sure what the cause of the bled was this time round though even with the early u/s's they didnt know why.
I know how scarey it is especially when you have experienced m/c's before it brings all the bad memories to the forefront again.
Im glad the bled has gone back to brown, but I know how scarey it is even seeing that. See if you can get some BT's done to check on the HCG levels, or even go and have a u/s done hun, to hopefully ease your mind. Maybe your OB will have a quick check too. I have everything crossed for you that everything turns out ok.
Its shameful to admit but, I went through so many HPT's to check that I was still pg for weeks until I could have my u/s. Sending loads of sticky vibes. hugs