One of the most important things for me was making friends outside of vet school. Find a hobby you like and find a meet up group. Even if I can't do everything fun, I can go listen to a birder, or a through-hiker, or a weaver talk about their experiences and grab a cuppa with folks that have other things going on than vet school.
Exercise. it doesn't have to be 'intentional' but hiking, biking, walking, gardening, etc helps immensely (dopamine release). Mountain biking and commute biking are my current additctions. I have introduced 4 other folks to mountain biking, 2 vet students and 2 non vet students and we all love it. We also letterbox a lot and have made a lot of friends doing so!
Cooking. I don't do it often enough, but I have a few cool recipes that I perfected during vet school. all are fast, easy, flavorful, and pretty healthy, and doing them repeatedly has made them good enough for company
Work. I run a dog training business. I only deal with referrals from a few specific vets and I work on my schedule. My clients apply for my services, and I am very selective, which means most of my outcomes are very positive, and it keeps me networking with others.
Art. I don't pick any of it up enough, but I sketch and paint. Occasionally its the only thing that will let me express myself. I also write...even just to vent.