I'm going to make my girlfriend upset with me
Why are you wanting to make her upset with you?
I agree, she thinks I don't love her
Your girlfriend loves you and doe snot want to be upset with you. You shouldn't be trying to get her upset as it may end up destroying your relationship.
I've been told that if she doesn't love me, why don't she leave me. I'm going to break this girl and make her feel like she has no one that cares about her.
It is bad to hurt other people on purpose. You should be more careful about how you treat people.