I'm not sure if I'm in love with my girlfriend
Why do you think you aren't in love with your girlfriend?
She does everything for me, but when I talk to her she is negative and talks bad about me when I'm not around.
I think your feelings are normal. It's ok to break up with someone you aren't in love with. Don't feel like you are stuck in a relationship, she may just not be the right one.
It's good that I talked about it, but I'm still not sure about it.
It can be a difficult decision. Take some time to think about it so you can make a right decision.