in-laws (kinda haha)

Erin • 21. Mama to a baby boy 💙
it's my boyfriends dads 50th party tonight and also I had plans to go out with my friends but my boyfriend asked me to go to his dad's birthday thing (who kicked him out the house and if it wasn't for me he'd be homeless) so I told my friends I couldn't go out and told my bf I would go but then I got home from a shitty day at work, I have an eye infection and I have nothing to wear so I changed my mind and said I didnt want to go. now my boyfriend is kicking off and saying I've let him down and that he wants me to go, even though he knows me and his dad don't get along and I feel uncomfortable around him. 
am I in the wrong not to go? I kinda feel bad for not going but then I'd rather not feel uncomfortable.