Im a 21 year old female but i struggle with

Patient: Im a 21 year old female but i struggle with not being able to eat a whole meal or more than one meal a day. No matter how hungry I am after i take 3-4 bites of my meal im completely full and start to feel sick. I went from 140 lbs to 110lbs and i include no kind of diet or exercise in my daily activity. I use to eat very well

Doctor: