Can my parents overrule me at 17 years old?

I have severe chronic nerve pain in my right wrist and after a severe allergic reaction to a morphine tablet i was put on i lost a lot of weight. Im 17 and weight 5 stone 2lbs (32kg) and am 5ft 4inches (164cm) in height. I was admitted to hospital where i was tube fed for a few days because of the reaction and then i was fine and improving, but my medication wasnt upped enough and i have been struggling to eat with the pain, and i havent been sleeping at night at all (i mean not sleeping at all, i may get 30 mins every 2-3 nights if im lucky). The problem is my mum and dad want me to go to a child and adolescent eating disorders unit to get my weight up but i want to go to this ordinary hospital so i can get better pain relief (they have a specialist unit) and management and then get my weight up there because i am getting more help, and i know that it is right for me. Can my parents force me into the hospital they want me in or can i get myself into the one i want? Can they say im not 'stable' enough to make my own decision? Please help me.