Mid twenties was a fucking horrible age for me, mental health wise. Serious anxiety, grinding numb depression, weird sense of dread, and fear I was going mad. It did pass, and so far my 30s are so much better.
The things that actually noticeably helped (apart from waiting for time to pass) were...
Running 3x a week, outdoors. Had never run before so did nhs couch to 5k podcasts to begin with, and found I loved it so just kept going. It helped me feel capable and gave me headspace away from everything, plus when I felt like I was so weary I wanted to die, feeling my heart and lungs working hard to keep me alive made me feel like my body was taking care of me even though my head was mashed, and that was really reassuring and consoling (swimming in cold sea gives me the same feeling, but it’s a bit bloody chilly for that in December!). I had pretty much stopped eating because I was so anxious, and running meant I actually felt hungry afterwards so started eating better again, then as my distances increased I knew I had to eat if I wanted to get through the next run and suddenly I was gaining weight and enjoying food again.
Good talking therapy. I was referred on the nhs and seen within 2 weeks (I think they had me pinned as a suicide risk) and it was really brilliant. Did 8 weeks, not cbt, I think maybe person-centred psychotherapy? Anyway, counsellor was great and some of the conversations we had still help me in tough moments now, years later.
Mindfulness meditation. Even when it made me feel silly.
Hope something there helps. I really do think intensive cardio outdoors is way more life/sanity-saving than we realise.