What Causes One To Lose Appetite?

I have no natural appetite, I have heart burn all the time. I can eat one bite of anything and feel full, but it gives me heartburn immediately that doesn't go away no matter how many Tumbs I take. The burning stops slightly when I drink water, but not enough to get food down.

I drink liqour sometimes to try to trick my belly into eating, but I throw up a black/scab-colorbrown stringy mouthful that feels acidic. My stool is bile green colored at times, and when it is, it burns and gets slightly foamy.

My stomache hurts as if I'm starved, but I just can't seen to get my body to eat. or get hungry.

I feel hot all the time, but I don't have a fever.