(((eating disorders TW)))

I'm so tired and so done with this BUT it's impossible to get help it seems unless I am dying I guess. I like in the uk so I'm supposed to get free healthcare on the NHS. Every time I have tried doctors just don't seem to care even though I'm under weight and weak (HAVE BEEN FOR YEARS) but my hearts fine and my bloods are always fine (I literally have no fucking clue why tho when I'm a mess) 
Like what do I need to do to get treatment???? Other than somehow get even worse???? It's been a good 5years in this horrific state but I have suffered on and off for 15
Does anyone have any ideas on what I should say to a doctor? I feel like complaining to someone high up but how do I do that? 
I'm so desperate and i really didn't want to post something negatively and kinda irrelevant on here sorry guys 😞