What should I do?

Performing arts is my passion, and always has been. I went to a specialist school and had a career that was beginning to take off and was just generally happy. I felt fulfilled, I enjoyed what I was doing and my family always seemed to be proud of me. But then last year they turned around and essentially told me it was time to grow up. That I'd never make a career out of any of it, I'd never suceed at it, that it was a huge mistake. At that time I'd just completed filming work for the BBC and was taking classes with the royal ballet so I tried to use that in my defense but it was minimised and dismissed. My mother told me that it wasn't a real career or a real degree to study for, that it would be a waste and that I'd come out of it with nothing. She reminded me that once I go to Uni the support I get stops, and I'd have to pay if I ever wanted to come home, so if I did something like that I'd end up broke and feeling unfulfilled. My step-dad just told me that people pretty much never do jobs that they're passionate about, and I should just let it go. They want me to go into something medical. It's not all bad, I do have some interest in it, but I have no passion at all. I see my friends talk about uni and they're so excited to finally be doing what they want to do. I'm not really excited for my course. I want to carry on acting and singing and above all else dancing. It helped me so much in life, and now I don't even get to do it as a hobby and it honestly breaks my heart.

My question is simply this: what should I do? What would you do?