I Am Trying to Find Who I Am

I've been in college 4 years now and don't know who I am, or what I wanna do with life. Talking to a therapist, I may not have a stable sense of identity with the way I grew up and the abuse I dealt with, leading to boderline personality disorder. Now I don't have multiple personalities like that, but my mood can go from 0-100 real quick or vise versa with no cause or catalyst.
I just need to look inward, and make my own purpose on this planet. It's hard though, and I'm struggling. Idk if anyone is in a similar boat or not, I just don't know what path to choose to go about my life.
But I am trying.