Granted, if you have no appetite, it may feel be that you’re not feeling good in other areas. Exercise is recommended in a lot of cases, but if you’re feeling sick, it may be best just to have a nap instead.
Make sure you’re as relaxed as possible; if you’re feeling tense and really don’t want to eat, your gag reflex might work up as you’re trying to eat.
It’s just as important of a psychological step to remember the practical (and necessary) health benefits of eating food. If you see eating as an absolute necessity, you may feel more inclined towards eating.