Why don't you make a list of things you will say yes to? So far we only have no's:

Meds - no.
Therapy - no.
Volunteering - no.
Studying - no.
Working - no.
Music - no.
Nature - no.
Exercise - no.
Socialising - no.
Spiritual things - no.

Here are some suggestions:

Travel
Arts and crafts
Mechanical work
Software creation
Quizzes
Animals
Reading

Even if you just try one thing you enjoy, it will start you on a path. Feeling better won't be instant. Sometimes you need to do things to distract you from feeling bad.