> I'm suffering because of it and it significantly limits my life.

> I don't want to go to a therapist

I don't understand this. But, if you really don't want to see a therapist you can try self-guided cognitive behavioural therapy from a book like "Mind over Mood" (this book is used in some English NHS settings).

Or you can try the website MoodGym: https://www.moodgym.com.au/