Do what you gotta do, man, but think about this before you go work full time at the diner.
Your parents are paying for your tuition because they want you to be able to get a job where you can support yourself some day. You have less than a year left and you'll be done. If you were my kid, I'd rather help you finish up school if that means paying for insurance until you can afford it on your own than see you walk away from it to go work full time at a diner. They didn't pay for that. Not to dog on cooks and wait staff, but anyone can get a job at a diner with no school required. I get not wanting to burden your parents any more than you have to, I hated it myself, but I know I'd be bummed if you didn't finish school and I don't even know you in real life and I can guarantee your parents will be bummed too.
Give it some thought. I know a few people who walked away from good opportunities and ended up working dead end jobs for way too long. You don't want that to happen to you.