You're surrounded by assholes. 90% of the time, this won't be a problem. 10% of the time, you're stuck with them.
But most of that time, too, you won't have any problems, because bullying takes effort too and assholes don't like to expend effort. So you're stuck with assholes, but you pay them no mind and they leave you alone. No harm, no foul.
Very very rarely, like once in a blue moon, maybe once or twice or three times in a whole year -- you've got a problem.
That's how big the problem is -- it's a few times a year at most. These are small people. They can only do small things to you. Yeah, those things suck -- but big picture, they don't mean anything.
Small pictures matter too, though. So what can you do to make it suck less? Because really that is still important, and I'm not trying to make light of it. Thing one is to be safe, so the small-picture people don't become a big-picture problem. That means fighting your way out is a monumentally bad idea, both because you might get hurt for real, and because you might wind up doing something you regret later. So screw that.
The teachers should be on your side. They should have your back. They don't. It doesn't sound like they're going to in the near future, either.
The key is to de-escalate the situation. Someone's giving you shit, your first (totally right) instinct is to give it right back. Don't do that though. Someone wants to fight, you apologize (even though you probably didn't do anything wrong), sound like you mean it, and get the hell out of that situation. Someone wants to take your money or they'll hurt you, fucking give it to them. Welcome to adulthood.
Why? Because there's only one way to stop a bully, and that's to beat the living shit out of them until they fear you like a mouse in a lion cage. That's not something you want. That's way, way more trouble than it's worth, and you're risking either you or some kid (yes, kid, they're all just kids) getting seriously hurt. Very bad things. You're not going to stop them, you're going to outlast them. And when you do, all their petty bullshit means nothing. You've got five weeks left? So fuck 'em. They're just something you had to put up with once, like a shitty christmas decoration. You're already done with them and they don't even know it yet.
TL:DR -- don't waste one single thought on them. Don't waste a single breath talking back, don't waste a single drop of sweat trying to handle things with your fists. Even though this happened to you, it has nothing to do with you anymore. That was all chapter one; you don't worry about anything but chapter two and three right now.