I'm going to confront my friend selling stuff I gave her
Why does it upset you that she is selling the stuff that you gave her?
I'm tempted to burn everything as it is a narcissistic attitude. I've been giving her things for free, but she never thanks me.
She should thank you for what you have given her, but you can't decide what she does with something after you have given it to her. Don't give her things for free in the future if it bothers you that she will just sell it later.
Should I stay pissed off because she gets on my nerve and I always get angry when I am around her?
You should stop seeing her and giving her stuff for free. Get rid of yourself that makes you angry in life.