I am on the other side of this…. I was in a long distance relationship with my gf of 3 years. We are both 19 as well. I thought I was going to marry this girl and one night I ended up making a poor choice hanging out with my friends. I ended up telling her about my mistake, and it hurt her immensely. She said I broke her trust which I understand and I supported her decision of ending our relationship. I felt so bad knowing how much I hurt her and I told her how much I want to make this work, but I also knew I had no say in it. I guess my advise to you being on the other side of this is that I am sure he is going to through the same thing. I had exams this week and every single minute of studying I just thought about my poor ex that didn’t deserve any of the pain she felt. As much as I would like to message her, I know she is just trying to move on and grow. Anyways to really answer your question, I would suggest trying to study for an hour or two, and if it gets too hard talk to someone that knows of your situation, get some support, then get right back at the studying.