I'm not going to talk to my girlfriend about things that upset me.
Is there any specific reason why you would avoid talking to your girlfriend about things?
Most of the time I just don't like talking about how I feel. I want to focus on more important things.
I understand it can be uncomfortable, but being able to be open with your feelings to your partner is an important part of a relationship. It shows that you trust them, and it allows them to better understand you.
Sometimes I just don't have the energy to deal with her. She has a high chance of freaking out over everything.
Relationships aren't always easy, and they require work. Keeping things from her because you don't want to put in the energy to work through the problem is going to cause issues in your relationship. You should try to talk to her more and explain how you're feeling.