I'm going to break up with a girl to pursue therapy for mental health struggles
Is your mental health declining because of your relationship?
Yes, I was fine with myself until she came into my life.
It's good you are seeking help and want to get better. Maybe ending the relationship is a good first step.
I feel like hanging onto them.
If she's making you feel worse while in the relationship then it cannot be beneficial to stay in it. You really should focus on your mental health.