how to befriend/approach a guy that keeps lingering in my mind?

Please help. I am going crazy from the obsessive thoughts about him.So basically everytime I see him, I will automatically turn into this "pretend I don't see him" and expressionless face (sometimes he definitely saw me but most of the times I think no?) but then when that moment past, I will regret and hate myself so much then spend the entire day convincing myself to pluck up all my courage to smile or say hi to him the next time we "meet" but then when we do I keep on doing the same thing and the cycle repeats.The thing is, I am a year older than him and we haven't introduced ourselves to each other yet although I must admit that I know quite alot about him from social networking sites. (I didnt follow him though and do not plan to introduce myself over the internet).Everytime I see him its either me walking in front or behind him in the walkway or us coming from opposite directions. I couldn't possibly talk to him in these situations right? We have classes to attend and it's just weird to rush up to a stranger and start talking, like what could I say other than hi. Other times like when eating, he will dine with his bunch of guy friends which even make the situation impossible for me to approach him. (btw I have never seen him talking to any girls) there was once though I saw him sitting alone in the library but then he never showed up again ever since. Basically we have absolute ZERO mutual friends and all the odds are not in my favour plus my already shy attitude and kinda lack of confidence is not helping at all! I am so sick of spending so much time thinking about someone. Can we just talk to each other already but I really don't know how? Argggh such frustration. TSR, please help me