Well, it seems there were several issue that worked against you, Seed.
First, it was her apartment and you were the "intruder" so to speak. You were
gone for a while and you both should have taken the time to get used to each other again before moving in together. It also would have been better to
get a new apartment (if possible) so she would not feel as protective of her own
apartment and things.
Second, she probably was looking for a more committed relationship in the near future, thus the objection of you going to college and not making any
money for the next four years. How could you support her and possible children if you're in school?
In conclusion: you both want different things in life, and are at different
stages in your life, it is all for the best that you both pursue your interests