Talk to Dietitian/Nutritionist on Loosing Collagen & Muscls

my age is 29 and my height is 5.4.I am single i always have heavy legs.I used to do tread mil but i was more loosing from my uper body then i started eating too less and mostly on fruits i lost alot of suddenly i stated loosing my skin collagen and muscles :( Now i look so old i got wrinkles under my eyes and lost my cheeks muscles as well. I am very upset and in dipression these days. I NEED SERIOUS HELP from nutritionist and dermatogist.I don't to look old and ugly at this plz help me in this