I was in similar situation, where I would sleep off daytime, then it messed up my sleep schedule for years. I got better once I realized that I am a zombie in that state. I advise going for a walk. Try to go a bit further every day. Just stop outside, it's funny to go home instantly, so have to walk for a minute. The this has two benefits - cardio on fresh air is good for physical health and makes you tired for the night, and for me it brought relief from mental pressure and gave space that I am safe to think about difficult stuff. There is something in act of moving that help with the head. It's also nice anchor - you are in control of his much you walk, where you walk, just do it, like guy from memes.
Be kind to yourself <3
Going thru similar shit right now myself I found an anchor in working out. I started from total zero - zero push ups, zero pull ups, zero sqats, zero crunches. I can do most of these now, with pullups to go still. But I also got into better mindset and learning discipline too. Good stuff that I've neglected for 20+ years.