Bella, you seem like one special girl. Your parents (and you) should be very proud. I am the mom of a daughter (also 17) who had her surgeries these past few months. Let me tell you, a parent will do anything and everything to make things right for their children.
You mentioned that you wish you had the pain and that they could be happy. I'm betting that they are thinking just the opposite. Parents never want to see their children in pain. We would do anything to take it away.
Money issues can be very stressful. My husband and I both have good jobs but we are always behind in our payments. We do have good health insurance so that isn't an issue for us. But worrying about paying for everything can be tough. But we would do just about anything to make sure our children are healthy.
Talk to your parents. Let them know how you feel. Be there to support each other. Remember that the most important thing for you to do right now is get healthier each day.
Have them talk to the doctors, hospitals, pharmacy, etc. They can work out payment plans, if necessary. Remember in the long run, you getting healthy will end up costing alot less then all the medications you would have to be on with UC.