There different factors that can trigger or behaviour one is your thoughts, Biological or environmental. We cannot do much about environment but if properly worked on thoughts and little bit of biology things can be different. A proper assessment is required if the depression is due to biological reasons only therapy or thinking helpful won't help. Sometimes medical intervention might be needed. Also thought about depression need proper therapy and not just think positive let's do things that make me happy type of approach. A 10 session thought Managment therapy is required.
Next Steps
See a psychologist, psychotherapist or psychiatrist online / offline
Health Tips
Depressions is negative thoughts about Future, self and others. So one need to target the hopelessness first. Also just in case you may have to take Low dosage of meds they are not harmful and with very little or no side effects.