Open Question: Quitting Being a Swimmer?

I have been competing since i was 5 years old and am now a month out from turning 17 making me 16 years old. At the moment i am really thinking about quitting. But i need adive or some thing...maybe i just need closure. This has been really the hardest thing ive ever had to do and i think i am actually depressed, the amount of crying and not breathing through crying i've done....i really loved my sport. I have had the highs and peaks, nationals being the highest ive been so far coming 4th in Australia as a 16 year old in 100 freestyle. But right now i literally feel like im swimming through a tree when im training and more so racing. I just cant get any speed whatso ever and it shows in my times. So im thinking ive burnt out. My coach when i told him today at a swimming canrival, said it was possibly because sometiome lasty year from about march to august i lost nearly 20kgs and was on the verge of being quite anorexic, but currently it has been put all back on again. AHHHHHHHH