You need to have your glucose checked, it may be hypoglycemia.
If you're burping, it may be H. pylori infection of stomach.
It reminds me of when I had a stomach ulcer, I was so very hungry all the time, or at least I thought it was hunger, eating took away the pain, and soon after, I felt 'the pain' again. I put on so much weight after, it wasn't even funny. Much later, I went to the Doctor, had an endoscopy, and they found that I had a stomach ulcer, it was treated very, very easily with some antibiotics and some other pill, which I can't remember, but loosing the weight was the really hard part. I strongly suggest you see your doctor, and unless she/he diagnoses you, I'd suggest to her/him an endoscopy to look for a possible stomach ulcer, and that could save you piling on weight which would result in other major issues. Here we have a liquid product:
http://www.gaviscon.co.uk/
I suggest for you in the liquid form, and if you don't have it in your country, ask your pharmacist/chemist for your countries equivalent, again in the liquid form. I may of course be wrong, but if I am, taking that liquid won't really do any harm, and it should settle your stomach.
Be sure to let us know how you get on, I'll be pleased with myself to have got something right. :P