How do I turn my life around?

Hey guys, this is my first time ever doing the reddit things but here I am. I'm 20 soon to be 21 entering my 3rd year of university. I've switched majors this summer to finance and don't feel like I have much going for me. I'm slightly underweight at about 165lbs. I go to the gym inconsistently, not consistent enough to see any serious results. I am currently training for a 5k. I probably won't land an internship next summer having a bit below average gpa and switching into the major after 2 years of university, I am behind compared to the others I am competing with. I don't have friends for the most part, I have acquaintances or I guess I do have some friends but pretty all of them, I initiate pretty much all conversations. I've cut off most of my friends who I feel anxious around and feel like there is too much tension with and was overall a bit of toxic. I've started the semester fairly well academically but I struggle holding that up. I am scared for the future that I may not be able to get anything going for myself in life. I have a part-time job at the moment that makes less money than I would like. I guess my question here is how do I turn myself around. How do I make more friends, more money, stay consistent in the gym, stay disciplined and overall just be the best version of myself?