I think I miscarried :/ I'm not sure. Should I tell my boyfriend?

We never use a condom but I'm on birth control and he always pulls out. 2 weeks ago we had sex and I started noticing my boobs getting bigger but I thought I just gained some weight. My back was hurting horribly today and I was a week and half late for my period and it came today but it was extremely heavy. I don't know what to do.