That really sucks about your ferret. I'd first find out whether or not I can have a pet of any kind in the dorm (or wherever you're going to live.) Then, get whatever kind of animal you want. I'm a fan of cats and dogs...and snakes...and geckos...and iguanas...
When my cat goes, I'll be quite bent out of shape, but I'll get another. It's not really a "replacement" either. I take good care of my kitteh, and I'll take care of another rescue kitteh well after mine is gone. Just don't get anything from a pet store.