>>91076540(trigger warning: blog post)
Lift. At least twice per week per muscle group.
Go outside and do some manual labor job or participate in some physical, productive hobby (as opposed to consumptive hobby; in fact, keep your consumptive hobbies to a minimum and keep yourself busy with productive works).
Clean your room and yourself and keep both clean (do your laundry and vacuum your room at least once per week and shower regularly), and do everything but sleep and rest outside of your room (if you have enough living space, of course).
The point is, you need some semblance of physical stress because it's good for your mental health. Also eat healthy, whole food, drink water and sleep at a reasonable time, and all that.
As for loneliness, there's no other choice but go out and meet people (and behave within normalfags' parameters). Would be much easier if you have your health and fitness (everything stated above) in check. Sure, it'll be overwhelming and awkward at first, but eventually you'll get better and learn to not give a fuck.