I don't know whether i should get an istance dog or not?!?

Hello i need some help on whether i should apply on getting an istance dog or not. I have M.E. and EDS hypermobility and i do struggle with daily life....I'm not in a wheelchair and used to be on crutches for about a year. Recently i have been getting worse with my joints and the pain and i have regular bad spells of my M.E. What do people think? should i apply for one? do you think i would meet the criteria for being needy enough and i don't know if my doctors would agree with it or if they would think it would spur me on in life. i am having physio at Great Ormond Street, and it's a very long process to build up my muscle strength. I am worried that i wouldn't get accepted for one or my doctors think i dont need one. I absoulutly love dogs and i would be gutted if i wasn't accepted which might be why i am hesitating, so i dont get my hopes up or something....I am 15 going on 16 in august and i am going to be moving in august . If anyone can help or give their oppinions on what they think of my situation that would be great x