College making me so depressed

I am so mentally exhausted. I am a third year undergraduate student on the pre-medical track. I have lab three times a week, and spend nearly 30 hours in class, when homework, studying, clubs are involved you'd wonder when I'd have time to even breathe. Sometimes I feel really hopeless, there is nothing for me to look forward to, every weekday is studying and every weekend is studying. I think about giving up all together multiple times a day. Most students get pumped for the weekend, but to me its no different from Monday, I wake up, eat breakfast and study until dinner time. Don't get me wrong, I love learning new things, but I feel like Im trading my mental health for all of this. I don't even feel like taking care of myself anymore, I don't even care about dressing up for class, or even drinking water. I sleep naked every night because I'm too exhausted to even put on clothes.

I don't have any friends at my school, literally no one, I forbid anything bad to happen to me because I'd have no one to turn to. Because of this sometimes I will overwork myself until I'm completely exhausted so I don't have a second to spare to think about how lonely I am, eating alone in the dining hall, seeing other students having fun and enjoying their 20s. I let it all pass me by. I think its to the point when I return to school on breaks, my parents see a difference in me, they see how broke down my academics have gotten me and a lack of social life. I think they've become aware that I have no one and I hate that they realize that because I don't want them to worry. I feel like I've I traded everything to become a doctor, i don't feel like its a mistake I just feel like I don't have a balance, I have no one to talk to when things go wrong, I have no one to tell about my day. I don't know what makes me happy because I've never lived, I never had a life in high school and now in college. If someone even asked me what I like to do for fun I couldn't even answer that, I've honestly been isolated for so long.

I am in a relationship, that is long distance temporarily, but I don't want to be so dependent on one person especially since that person goes through a lot and has went through a lot of traumatic events I tend to be the backbone even though I feel like the weakest link, but sometimes that phone call is the only social interaction I'll get the entire day. And obviously when communication is limited I feel really isolated, but I try not to let it show. So I overwork myself, that is my coping mechanism, there is always something for me to do or to study for.

I wish I had a friend. I've joined multiple clubs, I've made small talk in class, but it never has gotten anywhere. People will actually see me sitting alone and crack jokes about it. My perception of the world has become so skewed, it seems like such a dark and horrid place