If that is his response to your fears....my suggestion, drop him immediately. There are doms out there that not only have the ability to dominate you physcially, but mentally (as opposed to your current from what you've said so far).
University is a tough time...I'm going through it myself, and it's really easy to get addicted to something or someone else that your grade suffers. In the end, finding a good dom IMO takes time, for now, try other ways in satisfying your submissive needs (I think BDSMlibrary Academy does something of that sort), there are munches you can attend once in a while, try a role play. It doesn't match up to the real thing, but it's a start, and you can ease into your level of submissiveness. Take care though, don't fall for any guy that 'appears' to be dom, there are a lot of fakes out there that have the potential to hurt you badly by simply using your submissiveness for easy sex.
My university education is more important to me then anything else at the moment. Everytime I feel that I'm slipping, or something is occupying my mind to a limit it seems like an obsession, I play tennis with my best friend, or jog, socialize, and repeat this mantra that education is my future. It's what has worked for me. Try your hardest to find what searches for you and stick to it, you'll find the person you will truely want to submit forever.