I'm sure if you had a heart to heart talk with him (hypothetically) he would tell you that the way he's acting is ALL because of him and it has very little (if any) to do with you. If he had a problem with you he'd probably tell ya because he cares about you. It stinks that he's going through some stuff and I bet you wish he'd come to you for help and get closer rather than withdrawing, but most people when they feel sad or lonely or depressed or hurt in any way, they withdraw from people. They just don't want to talk about it. I'm sorry you feel lonely and I'm very confident if he knew this in any way he'd probably change or atleast he would apologize. Just give it time though! Trust in yourself that it will work out in the end, because it surely will! You have to go through trials to get to where you want to be in life. Nothing gets handed to you. All is well.