Butterfly - did you ask if your breathing too much oxygen or doing it too loudly yet today? I feel for you because I am working hard to repair some of the very same issues.
I did not reply to your first post only because I did not want to assume any of the same causes but your last one makes me feel compelled to ask you whether one or more of your parents was NPD? If so there are some good books out there you may want to read like "Trapped in the Mirror".
Never feel quite good enough? Feel like you have to convince others that you are worthy of acceptance? Get way too upset by criticism or elated by praise?
Ironically, my wife and I had some of the same issues in our childhood and it gives us a chance to share some very scary and difficult thoughts and hear 'me too!'.
You might want to google a bit on adult children of NPD parent(s) and see if it hits home. The good thing about finding out thousands of others are screwy in the same ways I am is that a bunch of them also got better and happier in the same ways so there are maps to follow and the comforting knowledge that I'm not worthless, just a little f---ed up and knowing how, where and why I react the way I do helps make it easier to catch myself and stop. I'm also a tad OCD and ADD so I focus really hard but only for 3 minutes at a time... and I laugh at it now.
It might help you to also think and research a bit around how our 'quirks' are not all bad. My OCD tendencies make me very very good at what I do but under duress they become a liability. That is true of many traits associated with various 'disorders'. Just like those born without sight learn to make better use of their hearing we learn to use our quirks as tools and can benefit from them or be destroyed by them depending on whether we learn to see them, understand them and manage them better.
As for whomever convinced you that you are not good enough, the recovering person in me says feel sorry for them and forgive them but since I am still a work in progress the rest of me says f--k'm, you are just fine and please tell them to kiss my ass.
...BTW, one manifestation of my NPD parent background is that I am a terrible conflict avoider in my close relationships but out in the world when I encounter bullies of the sort that like to pull wings off butterflies I am the reverse - I go after them and try to expose them for the weak, insecure, cruel, rotten bastards they are. In other words if I am not very careful I act just like them, the only difference is that I choose a bully rather than a butterfly to attack.
You are OK, probably better than OK. The sooner you get that the sooner you can drop that awful burden of fear and doubt that is so soul crushing and self defeating. Hang in there!