<human>: Can you provide a brief rundown of the text in within 3 sentences?

About 2.5 months ago my then friend, now gf invited me to her grad party for college (she never had one in high school). This past week I was given the opportunity to work that  night for roughly 60 an hour. I explained to her that it would help a lot with bills but she's still cold and angry at me. 

Am I an asshole for possibly not attending her party? I never commited in the beginning, I said most likely but I'm not sure. 

Also this is the second time she's gotten angry at me for the possibility of not attending something. The day before her birthday I took her out for a day full of fun at an amusement park. The next day my friend who I haven't seen for 4 years came into town for 1 night on the same day as her birthday. She got angry at me for contemplating the idea of going, although she gave me consent (not that I needed it).
<bot>: gf wants me to go to her party she invited me to 3 months ago. I never committed, she's angry at me now that I might have to work.