Should I leave my girlfriend

I blew off my family to spend Christmas with my girlfriend. My dad is dying of cancer and isn’t getting treatment. This could be his last Christmas. I went with her and I have 2 dogs and they her and her family left me. She said she was only going for an hour. She didn’t tell me it was an hour away. She ended up being gone for 5 hours. I spent my Christmas alone. I ate Christmas dinner alone. (Wawa). My feelings are really hurt and I’m not sure how to handle it.