I feel embarrassed for having a job in high school. How should I handle things?

So basically, I go to this really prestigious private school and I'm a senior right now, and about a year and a half ago or so, my parents completely cut me off financially. Even though they're really well-off, they refuse to give me money thinking that I should "work for what I want and need instead of having it all handed to me" because that's how real life works.
Long story short, to be able to move around and do all the things the people at my school do, I have to work two jobs and its STILL not close to enough. It's just so embarrassing. I mean, they keep on dragging me to places I honestly can't afford, but if I say that it's going to be really embarassing and also, it's going to seem really unrealistic because they've seen my house and the way my parents live. The only person I've told is my boyfriend. I can't help but feel ashamed that there's just so little I can afford, and also a bit jealous of my friends, who get to do everything they want. I mean, their parents get them Range Rovers and Mercedes SUV's and all I could afford to buy myself was a used Honda Civic from 2000.
My friends are just making it so hard for me to feel good about myself, and if I tell them I KNOW they're going to make fun of me. They look down on the sort of kids who have to get a job through high school. I already tried asking my parents and failed to achieve anything, I feel like they're just trying to ruin my life.
Any advice? What should I do?

Same exempt I'm poor

Do what you have to do, which is what you are doing. If these friends of yours will look down on you for working and not having as much money, they are shallow… And weak.

You are not weak, and it seems your parents arent either. So swim or sink, its up to you. You sound like a swimmer to me.

Honestly, your parents aren't fair to let you handle everything on your own. But, on the other side, having a job and doing everything for yourself will make you become a better person and you will know how to deal with life better than your friends. If they would make fun of you for something you can't change, i would dare to say they're not your real friends. Nobody should be ashamed for doing something useful with their life and accomplishing something.
Seriously, look at it this way. Your friends have better cars. But you said it yourself, their parents bought it for them. Doesn't it feel better knowing that you deserve to have that car you bought, that you earned it with your own money? Thanks to your parents, you will become more mature and handle life better. Trust me, later in life you won't think it's so bad.
Good luck with everything, and don't feel bad even for one second for being more useful than your friends.

Quite a few things I want to say in response to this. If your friends are gonna tease you and are making it hard to feel good about yourself then, no offence but, are they really your friends? Friends are supposed to support you through thick and thin, not dismiss you as a lowlife if you have to work. I also think it's a tad harsh on your parents side for not even trying to help you and for just making you have to do evereything by yourself. I can agree with them not wanting to just hand you everything you need but they should help out a little bit. Also, if you explain to teachers why you can't afford to do extra curricular subjects then (I'm not sure if you have this where you live but you can have it in england) they can organise bursaries for you and they can help pay for all these other things. The fact you're managing to keep two jobs and go to school should also be applauded rather than frowned upon, in my opinion because hell, I doubt all those other spoiled kids getting expensive cars could do that. I'd suggest telling your friends and if they give you a hard time for it 1. They aren't your friends and 2. Just tell a teacher that they're bullying you. Money or no money, you're still a person and deserve respect. If they're not willing to give you that respect then just leave them because they don't deserve to have a friend.