Miscarriages

When I was 15 my boyfriend and I were still together, but we were fighting and just not talking as much and I go on runs around my neighborhood when I can't get into the gym. So one day when during that time frame of us not talking I went for a run and one of my friends from middle school stopped me and asked if I could help him get his bike out of some mud; we have a pit area in the back of the neighborhood and we both race Motocross. I said yes being a nice person and after I helped him he pinned me against a tree and long story short forced me to have sex with him. His condom broke and as soon as I could get away I did and ran home. My period was very, very late after that so I took a test and it was positive and a few days before I was going to tell my parents and his and him I got this really bad cramping pain and I went to the bathroom and I was bleeding a lot. As a 15 year old who honestly didn't know that much about sex and all that I dismissed it as a false positive and my period because I didn't want to think I had a miscarriage that young. Now I'm 17 and with the same boyfriend and I recently found out I was pregnant by a home test. I was going to go into the doctor this week to confirm, but last night I had a horrible pain and bleeding again. This afternoon I went into the doctor and was told that I had a miscarriage at about 7 weeks. I'm terrified that when I'm older and actually ready to support kids that I won't be able to. These are just two times that I'm 100% sure of it being one, but I'm about 50% sure I had one a few months back. I've been with the same guy for four years so it's not like I'm out messing with guys. I just felt like I should share these times. I really don't know why though.