Hey. I'm really sorry that you're going through that. Is it possible for you to go with someone you can rely on for emotional support. If not your parents, maybe a sibling or a cousin or a close friend outside of the school?
When I went to my formal, we went to a park to take photos and then to the function centre to have the dancing and dinner. Try to ask the school what they'll do. If they have a before event, maybe just go to that and skip the parts you don't look.
I don't agree with your parents idea of tough love. In my experience that seems to make things worse. Are you seeing a psychologist? Maybe you could have them tell your parents not to do that. Can you voice that to them?
I really hope things work out for you. You were really brave to post this.
