man help: I’m not eating and I’m never hungry… - Help.com

Could be your stressed out over something? Or your appetite has been reduced over time so your stomach has shrunk in size?
Try eating something in the morning, regardless of how small a meal it is just to get your body going. Come lunch try to eat something again, avoid the likes of mc donalds, make yourself a sandwich or anything wholesome.
Best to try make it a part of your routine even if you’re not feeling particularly hungry, otherwise you’ll end up sick for it :)

And I thought I was the only one!

The less you eat, the less hungry you will have and the less you’ll want to eat. It is a vicious cycle. There are also lots of other circumstances that may cause you to be less hungry than usual, such as smoking or stress.

In order to break the vicious cycle you have to force yourself to eat. A lot! Eat until you are full, and then eat some more. You’ll get more and more hungry again with time.

if you feel you can’t eat for longer than 4 days i recommend you go to your doctor just to rule out any nasties. Exercise always makes me feel hungry, why not try a brisk 10 min walk (i do mean brisk) every day and see if this helps or more if you are able.