Yup, like everyone else has done on the internet, I too am about to drop some unsolicited advice on how I've been keeping sane during quarantine. Hopefully this'll be helpful, and if not - well, use the googles to find other articles about this exact same topic.
Being a college student, socializing isn't really too difficult. Okay, making friends is hard at any stage of life, but at school most of them are always within a 10 minute walk from your dorm or apartment. Within the first month I realized that socializing remotely requires a lot more conscious effort and scheduling. With the vast range of entertainment available to us it's really easy to forget to check up on friends when they're not physically present in our lives.
Staying focused when your bed is only a few feet away is something I think everyone has struggled with in the last few months. Sure, calling your friend to work together on stuff doesn't have the exact same effect as studying in a library on campus, but it's been surprisingly beneficial to me. Plus, you also get to hit two birds with one stone when you inevitably give up on working and just socialize/hang out on the call. Friends not available? There's this really useful site that'll connect you with strangers to cowork with.
Channel your inner 18th century sea captain and start your own log of what you day by day. I had been keeping a journal pre-covid because I read somewhere that it's a good habit without actually paying too much attention to the why. Honestly, I didn't really take it too seriously, and a lot of my 2019 entries are up to a month apart. But recently journaling has been a lot more useful, even when there seems to be fewer things going on to write about. It lets you organize your thoughts and feelings and better understand how to deal with them. Bonus: it's doesn't require looking at a screen.
Yeah so everyone says to pick up a hobby, but in the first few months of quarantine I was still not getting the seratonin I expected from them. I tried listening to podcasts, watching a ton more of Netflix, grinding out leetcode, and reading books from high school, but all of them ended up feeling like chores rather than hobbies. This isn't to say that these are wastes of time, just that it didn't feel like I accomplished anything.
Especially in a time where so many things seem out of our control, I've found it nice to do hobbies where there's something produced, or you're able to express yourself in. For me, it ended up being programming side projects and writing this very mediocre blog, but I have friends who've dived into crocheting, embroidery, guitar, and otns of other cool stuff.
Of everything on this list I think this is both the easiest and the most rewarding. Just go outside, walk around the neighborhood and plug in your earbuds. Obviously wear a mask and don't invade the personal space of others. I've walked the same route around my neighborhood at the same time for a consistent 45 minutes every day, and it's done wonders for my mental health. Besides getting Vitamin D and breathing air that didn't come out of my family's mouths, it lets me (very lightly) exercise, relax, and be alone with my thoughts.