I'm not going to tell my girlfriend that I took days off work so I can relax and play video games
Why did you not tell your girlfriend? Did you have a feeling she would be mad?
She was always telling me to bring her along to watch movies or explore the city together.
You shouldn't hide things from your girlfriend. Relationships are built on trust and you aren't being truthful.
It's my business and it's not her's.
If you want to be in a relationship you will need to learn how to share information about yourself with another person.