I Have Not Been Feeling Well For The Last Week,

I have not been feeling well for the last week, my symptoms are lost of appetite, pain in my left side of lower abdomen inter side of my hip bone, and my head will get warm and I will sweat, then it goes away after about 20 minutes, then about an hour or 2 it comes back, also I feel very tired all the time, I am a 45 year old man. I'm not sure if its food poisoning, if I possibly have an ulcer, or a kidney issue. Also I always feel very dehydirated.
I am a smoker about 1/2 pack a day and drink beer about 6-12 cans a day.