I feel absolutely terrible for hating mental illnesses, my girlfriend made me this way.
How did she make you hate mental illness?
Because she continued to voice her opinions about it. I told her I didn't want to listen to it anymore but she kept on talking about it.
I'm sorry she manipulated you that way, but you need to think at your own accord. Mental illness isn't something to scoff at, it is very serious and trivializing it like this is detrimental to the people who are suffering badly. You make them feel even worse.
I can't stop her. I've tried but I can't. What should I do?
I know you are he tried to stop her, but I think you should give one last attempt to communicate with her that you don't agree with what she's saying. If she continues to disregard what you're saying, it may be time then the relationship.