Bad taste in mouth/ Thick saliva/ Feces.

I have been having feces smelling breath for about two years now. At first I noticed it got worst when I drank coffee, ate sweets, or even just bread. Then it got worst and it would get pungent with anything that I ate. I have been having to hold back on many things because I am afraid to talk to people and have my terrible breath offend them. Being a 22 year old student in college it's impossible to avoid social interactions and I have had to do lots of research. So far I've been brushing my teeth like 5 times a day, flossing, and tongue scraping but it doesn't seem to solve my problem. This past week it actually got worst and chewing gum will not cover up the smell anymore. I'm at a loss. I have a bad bitter taste in my mouth and I constantly drink water but it persists. I have post nasal drip, GERD, an aching root canal molar which had to be redone but was still hurting after the procedure. Those are all my culprits and I want to know how to fix the problem. It's debilitating :(