Scared

So last year around the middle of September, I had a miscarriage and the doctor said because I was 2 months into the pregnancy, that there was a good chance I won't ever be able to have kids, I was 18 at the time, and my doctor growing up, said that it could of been just my body. That I couldn't carry or it could be that my boyfriends now ex boyfriends sperm was sterile, but the same month he got another girl pregnant, I have been with this guy for almost 6 months now and I brought it up to him, he says if anything we will just adopt we are to get married next year. What if he starts feeling differently, because of me not being able to get pregnant and him wanting a family? I'm scared I'm going to lose the love of my life and I'm scared I won't ever be able to have kids. What do I do??