That's really rough! I can sympathize with that feeling of not being good enough... or good AT ALL. It doesn't matter what age you are. A parent's impact on your self-belief is huge! It helped me to learn about TA.
I made attempts on my life at 15, and thought that was the worst of it, but I really hadn't been living after that. I learned in TA about "scripts" and "drivers" we get from our parents. It's hard to accept, but I learned that my mother's behaviours...or our "transactions", had lead me to behave so as not to exist. My driver was "do not exist".
If you think about it, everytime someone says "Don't be..." or "Don't be so..." ...you maybe stop hearing the specifics of the criticism, and just internalise the message "Don't BE".
It's not even likely to be intentional. Some parents just CAN NOT cope with their kids