Looking for a decent community/forum which is about mental issues

Damn. I hope you're feeling better by now.

Might sound weird, but Twitter can be very helpful. There is no shortage of empathetic people, it allows lots of activity beyond mental health.
The one big challenge is that you must establish or find your way into a circle of people first, before it becomes the effective tool it can be.

There are lots of Reddit subreddits for different mental health issues. Every time I join a Discord they are never active for very long. (If you find a good one let me know!).

https://www.mentalhealthforum.net/

I think maybe something like this one. It looks active. =)
I hope you are feeling much better.

https://checkpointorg.com/