Why do People Date in High School?

My boyfriend and I have been dating all of high school. I got denied from my dream college after they lost my application for 3 months and had the wrong ACT score on file. I wasn't smart enough, and now my boyfriend and I are being separated because I messed up and didn't do enough in High School. His overbearing mother barely lets us see each other and tells him that he spends too much time with me. He has been gone almost all of august and his unexpected family vacation just got extended extra days. He comes home 2 days before he leaves. I will only see him one more time before he leaves. I don't know if it is realistic to say that I have met the guy I love in High School, but I know that I am not ready to give him up yet. I am used to doing everything with him, and am having trouble believing that I will be able to anything without him. I don't want to lose him, and in order for me to transfer to his school I need at least a 3.5 GPA, a GPA score that I couldn't even achieve in High School. I can't wrap my head around why people would even date in high school when you are just going to get torn apart. I feel stupid and am miserable almost all of the time. I don't know what question I am really trying to ask here except "what the Hell." I want to say "why me" but it happens to a lot of people, and it's cruel and I am dreading college more than anything in my life. If you have any words at all, help.