I'm hungry but after a bite of food ill feel sick

What country?
How old are you?
Male or female?
How long have you felt this way?
Is there a 'spot' that feels sick, or is it all over your stomach and or abdomen?
Have you had had your appendix or gall bladder out?
Healthy diet, fast food and junk, lots of spices, what?

I could ask a million more questions, but a good online 'patient' knows what to say without being asked.
Therefore - see a doctor!