Fucking brains, they can suck. That's depression. I've dealt with it my whole life, and only just recently got to a level where I'm pretty okay most of the time. For me, what ended up being effective was therapy, finally getting and staying on medication.

I don't want you to have to deal with this for the decades I did. Find a doctor. Start with your GP if you need to. It's going to be hard to find mental health care, and even when you do, it's going to be hard to keep them on your case. The first, or second, or third person you find might not be the one for you. They might just stop returning your calls.

Once you do get the right person, it's probably going to get worse before it gets better. You need to talk and think through your issues; they're going to guide you through that process and prompt you as appropriate. This is addressing your most difficult troubles, shit you've been avoiding. Not any fun at all, but necessary.

Something you can do right now is recognizing thought processes you don't want, and consciously correcting yourself. Example: I was raised to be fairly racist. In my early 20s, I finally decided I didn't want that for myself anymore. So when I found myself thinking things about passers-by that I recognized were leftover from my childhood, I purposefully reminded myself - sometimes out loud - "That's a person just like I am, doing person things, just like I am." I know this sounds like Stuart Smalley "I'm good enough, I'm smart enough, and gosh darn it, people like me", but I am telling you that it can work. It's effort, and it means you have to actually address those unwanted thoughts right in the moment, but please try it.