10-12 hours/day is a lot of studying time. I'm assuming you're following some kind of schedule to study for the DAT. Add to your schedule things like "meet my friend Sarah for coffee" and "going on a 30 minute trail-walk with Dave". Doing things like that twice/week is not a huge sacrifice time-wise (maybe takes up 1/1.5 hours at most). The payoff is huge though, if it helps to prevent burnout. Also consider cooking dinner once or twice a week (if not more). It always feels like a small victory cooking good food, and it makes you physically healthy. Balance that with the gym or running once or twice/week. You can always cook or go to the gym with a friend, too. Now you've got an activity that will take up 1 hour each day that will make you healthier, prevent burnout, and help you score better. I'd also consider having one day/week where you do much less studying (maybe 4 hours or something). Make that your dedicated review day. You'll get some relaxation time in without feeling guilty. You don't have to incorporate all of these ideas (or any of them), of course. This is more or less what I did, and it worked out well for me. You need to maintain your well-being (physical/mental/social)!
ex) M (coffee) Tu (gym) W (cook dinner) Th (walk in park) F (gym) Sa (cook dinner) Su (relax day)
If you're miserable and unable to get out of bed, act on it now before it gets worse. Also, always worth mentioning: if you are struggling with depression, getting help is always worth looking into. Many, many people in this field suffer from depression. Not something to be ashamed of. Idk if that is the case, but it's worth bringing up.