Having a lot of problems and arguments with my Mother

Hey people. I’m having a lot of problems/arguments with my mother. She says I don’t do anything, I am worthless and a last cause , etc. In the beginning I was feeling down since it’s my own mother telling me that. Honestly, I don’t give a sh1t now. I was in the army reserves on part time while being a full time student. I quit the reserves so I can concentrate more on my social life, my girlfriend and my schooling. I am currently in college studying Pure Sciences (Math, Physics and Chemistry). It’s pretty much the best program you can get in Quebec, it allows you to go anywhere. I’m getting good grades, want to go to engineering. BUT my mother is constantly telling me(renouning me as a son =/ ) that I’m not doing anything for the family. I don’t drink, I don’t do drugs, I don’t go to parties, I do nothing bad whatsoever. Now she puts me an ultimatum : I have to live on my own. My dad is always on my side, I have no problems with him. I just don’t know what I can do more than what I’m currently doing. I haven’t even been to a single club, so I won’t spend money for nothing. What’s the best thing to do here ? I want to continue my studies, get a Masters in engineering. I can’t study and work part time to pay for an apartment; I won’t have time to spend with my girlfriend. I want us to get engaged next year and live on our own somehow. I won’t make it alone. My options are … stay in school but live where !? or get back into the army on full time, which will terminate the relationship between my girlfriend and I. I’m stuck. Any advice? PS. This question is a bit too long. Whoever can, please take your time to read it. I would appriciate any help. Thank you