you seem to suffer from bad digestion. Gaz can be two things
1- Dying candida
2- Bad digestion
With the bad smell though it is usually bad digestion.
Short term: raw veggies and broth, long tem: digestive enzymes, a Liver Flush or the cleansing salad (//www.curezone.org/blogs/m.asp?f=308&i=8) are your options.