>But most of the time in my life I've felt empty, doubting myself and struggling with a weak sense of self and unhealthy thought/behavioural patterns that are hard to shed off. I feel like I've lost any passion for anything, and don't know what I want or need.

You've got to look inward and figure yourself out - that could fix a lot of the other things you brought up.

If you know yourself and your ethics very well and you work hard to live them out, you're probably happy no matter your circumstances. Meditation or long boring walks can kind of open up your subconscious so you can start doing that; you can just wait until a random thought pops in your head and start pulling that thread, ask why you thought that, where's that coming from.

Also taking psych/life advice from strangers on the internet is pretty dangerous.