My girlfriend is being stingy, how can i change her mind and show her what i do for her?

My friends are all going home for college this weekend and asked me to meet up with them and we are all hanging out Friday night. When i asked her if she would go with me she was like no im not going home till saturday and i was like why not. she said because i dont want to. i was like well i do alot of things i dont want to do for u but i do it to make u happy even if i dont want to. she said well thats your choice. I let her keep her dog at my place even tho im not supposed to have pets here and i take care of him, i go to her friends parties and hang out with them every weekend even tho i dont want to because some of them are horrible influences and i hate doing the same thing every week. I really like her but she doesnt understand how much i do for her and i dont know what the big deal is about asking for one thing for a night. How can i convince her to go? What should i do if she is this stingy?