Exercise releases endorphins which make you feel less like shit. Find a bodyweight home fitness thing appropriate for your current fitness (home calisthenics, kettlebell, jogging, idc). After 2 months of that, your mental health should be +1 or +2, use those points to power you through the next thing you need.
Find the things you do in life that aren't helpful in achieving your goals and substitute different behaviors for those.
I personally use the nefarious and manipulative psychological technique of talking to people, determining what complaints they have about society, and explaining how capitalism and the government that supports it are the root of the problem.