I havent gotten pregnant

My bf finishes inside me and has for a while and i still haven't became pregnant. I assume it'll happen when its supposed to and it hasnt happened yet. I know i can get pregnant i had a miscarriage with my ex but now im like hmmm is it my bf? Or maybe its me because ive gained weight and im stressed off and on. We also dont do it alot when im ovulating but still something should have happened by now if either of us could concieve. Hes stressed alot too recently i wonder if that has anything to do with it