I'm thinking of leaving my prom group and not going since it is falling apart
Why are you so ready to give up on the group?
Because I spent a lot of time and effort to make it work, and I'm tired of it falling apart.
Your prom only happens once in your life. You should go. You should not abandon your prom group like that.
I just want to do something else, like hang out with my friends and not go to the prom.
I still think that you should go, at least for a little bit. You only get this chance once, you should at least experience just a little bit of it.