How can I convince my mum not to send me to school?

Basically, theres this big festival going on tomorrow and pretty much all my friends and all the girls in my class are going except me. Its an excursion. I've told her this and she was saying yes until her boyfriend came and she got all "NO. You have an education you need to learn." I've tried to explain that I am not learning anything in class because we are working on our assignments in every subject. She gets convinced but then seems to forget everything I've said and says no. I have science, math, drama, and history. I'm pretty much going to be the only girl in my class there and all my friends are going. Im going to be completely an utterly alone.

One of the main reasons is though I have 3 lots of homework due tomorrow and I haven't completed any of them. I did't tell her that though. She'd call me out on lying when I was just saying "I want to work on my homework." I can't say I'm sick now obviously, but any more strategies to convince her. She was fine until she started drinking a little and her boyfriend came over.

Please no stuff like you need to go to school or something. I just want actual answers.