Maybe someone in here can Help Me. Very Bad Taste in my mouth...

I have had a very bad taste in my mouth for months now and it's driving me crazy! When I get up it's not as bad as when the day goes on. I brush, gargle, and even use Hydrogen Peroxide and it still comes back. When I'm eating and chewing gum that helps it, but as soon as I stop either one it comes right back. I'm very frustrated here can someone help please? I have noticed after chewing gum all day I get the taste back and also a kinda chalky taste also. I have noticed later in the day that my saliva gets thicker also. I have also used a tongue strapper to try to solve this problem. It seems to be coming more from the roof of my mouth and top of my teeth area then anywhere else. I went to a Dentist and he cleaned some tarter from my teeth and it's still there. I went to the Doctor and he gave me Protonix because I have reflux and he thought it could be that, but that doesn't seen to help either after 2 weeks of it so far. I am just wandering if I could have some type of baceria or virus that a anti-biotic can take care of. PLEASE HELP I'm going insane over this. Oh yea no medications other then above either!!