How long after i stop takng birth control will it take to safely carry a baby?

I miscarried shortly after getting off b/c,which means I got off of it and 2 weeks later had what I thought was implanation bleeding, and I did test positive after the imp. bleeding started. And then two weeks after that I miscarried. I am thinking I miscarried because I conceived a week after getting off of it and possibly the lining of my uterus was too thin to allow for the embryo to stay put. My doc said to wait until my next normal cycle until I try for another baby, so that should about 8 weeks from the time I stopped using b/c. Does anyone think that's long enough for the lining to thicken so that I don't mc again?