I Don't Like Food

Food has become my enemy. I use to enjoy eating, cooking, trying different kinds of food. Now it seems no matter what I eat it bothers me, almost making me sick. Every day my choice of what I can eat is getting smaller.
I've been to doctors and every test shows no problems. Yet I keep losing weight. I manage to eat something, just I have food in me. I don't know what the problem is, or how to correct it.