Just read your post and can feel all my old emotions coming back. I was devestated by peoples reacations to me. I spent thousands of dollars on products and procedures. The people that I expected compassion from we're some of the worst. I would brush, floss, etc for alsolutely hours a day. I came to discover that I must have an alergy to run of the mill toothpastes such as Crest, Colgate, etc. I suppose it's the sodium laureth sulfate (spelling?). Then I purchased a "Sonicare" electric toothbrush. It was very expensive but in retrospect I wish I would have bought it sooner. When I think what I went through I would buy another a hundred times over. And ESPECIALLY important for me is to use only "Tom's" spearmint toothpaste. It has helped immensely. "Rembrandt" mouthwash is good too. Sometimes I get absolutely no reaction from people. It's amazing to me since I remember how I bacame serverely depressed and almost a recluse. I lost faith in mankind. All that kept me going back then was my faith in God, prayer, prayer, prayer & finding someone who wasn't judgemental (and no sense of smell)that I could talk to. You are NOT ALONE and DON'T GIVE UP, it may take a a few months or up to a few years but you'll get it figured out. You'll have set-backs too. I pray you find your answer. Don't give up.
As for possible Body Odor
here's my experience. My husband developed a nasty odor over the course of a month or so. I could smell him from 20 feet away and it would leave a lingering smell for hours. It was a very sour, metalic smell. I bought him all kinds of soaps such as betadine, scrubs, etc. Then I remembered how certain shampoos build up on hair. Also, swimmers get chlorine build up. Since he's a hairy guy I figured we needed to get a product for removing chlorine and metal build-up on hair. There a bunch on the market. You can find them at most drug stores such as Walgreen's or at hair salons. Avada (a hair care line) has a good one too. When you shower use it not only in your hair but all over your body and turn off the water for a few minutes to let it work. Use this process each time you shower. It took a couple weeks for it to be gone. I thank the Lord. I felt so bad for him because he couldn't smell it (my saving grace that he has a deviated septum and didn't leave me during my "trying" years)and I wanted to help. Again, thank you Lord.
I always wonder why my breath problem took so long to conquer and I've come to the conclusion that it made me who I am today. I became so comfortable with myself and my thoughts and opinions. There we're so many years when I didn't share them for fear of offending with my breath, but I sure did think alot about what people we're saying and what I'd like to say. I developed a lot of empathy during the ordeal. My heart goes out to you. Don't give up.