Im not the best at advice but i can validate most of what youre going through you are not super dramatic you dont need to be "normal" (that term is relative no one knows what it means) and to call you a "teenage girl" is incorrect obviously. Its meant to demean your mental issues and help you push them aside but it doesnt seem like the right way to go about doing so. for now take care of your wounds wear long skirts/pants and avoid sharp objects as much as you can, if you have the patience to scratch you should also file your nails down, and talk to your gf seriously sit her down and tell her whats happening she should understand or at least try
best wishes and good luck!
[Im operating on a lot of assumptions here so feel free to correct me]