I said I was busy because I didn't think she would see it.
Did you say this to your girlfriend? Why did you tell her you were busy?
I'm trying to break up with her by being a little harsh.
These are selfish feelings you are having. It is not good to lie to people. It will make your life very complicated.
I'm only trying to protect myself.
That doesn't make it okay. If you want to break up, be honest.