Hello again! I thought I'd post an update if anyone is curious.

I have reached out to some family for venting, and it has helped slightly. I do have plans in the next couple days to see the University counselor that is available to me, I'm hoping that it might be of some help to me. The idea of having to go to the appointment does worry me, but I believe I'll be able to overcome it.
I did look into the codependency thingy that sarahsweets posted, and I do think that sounds relevant enough to me to continue looking into it. In regards to me being the person people talk to, it's kind of difficult to describe so I'll do my best. Basically, if they don't vent to me, they vent directly to my girlfriend. This wouldn't be so bad if they could vent in a civil manner. The best example of this is my girlfriend coming home from the mental health facility that she had to stay at for days and my sister yelling at her when she walked through the door for the anxiety and stress she put her through. Obviously, not the best way to be welcomed home in such a fragile state.

Anyway, I do appreciate the advice and stuff given by everyone. Thank you everyone for your help, and please wish me luck tackling my newest challenge. Mountains of schoolwork and a potential failed class due to attendance.