To be honest if you can't have a relationship when you're at school, you won't find it any easier after, either at uni or at work. There's always work to do, so its impossible to avoid relationships just because of this. It is easily possible to have a serious relationship and achieve all your academic goals. Though the fact you have "put him down", as you described it, probably hasn't helped your relationship with this guy.
If you like him, try and get back with him. You don't have to be with each other everyday, just see each other when it suits. Besides, its good to have support through a very stressful A2 year anyway!