What do you do when you just DON'T want to eat?

I always eat, my problem is i don’t get full very often! I used to be really good with my diet but lately i crave sweet stuff all the time, i think i’m just looking for an energy boost or sugar high.
Maybe you have no appetite because of depression. Whenever i get a vomiting bug or just fell sick i go off food but i keep eating anyway cause i know i’ll just feel worse if i don’t. Maybe if you try to eat small meals regularly you will get your appetite back. You could also try doing exercise that always increases my appetite!