Odor / Ds ??

I wasnt sure where to post this, so I chose digestive system ect, because im guesing it might be a problem concerning my ds.

Im 19, been smoking since I was 15, and besides that, I thought I was in perfectly good health untill about 2 - 2 1/2 , years ago.

Over the past two years ive had a problem with what I thought was, halatosis. Appearently, after talking with a dentist, after a few years of neglect, he cleaned my mouth up and told me that the cause of the odor wasnt becasue of my teeth, or gums.

Ive had started to suspect its not halitosis after the second year now and the dentist telling me what he did, because I took care of my teeth pretty well, and no ammount of oral heigene was/is helping.

So now that ive checked with my dentist, and he says there isnt anything wrong with my mouth/gums that might be causing this, ive started to look into other causes for my symptoms.

Basicly, symptoms include - horrid smell excreted from my mouth/nose (when I breath, any air coming out, is going to smell really bad :p). I cant smell it too much, but if I try I do, and everyone around me is quite aware of it, judging by their reactions and remarks. (embarrassing to say the least)... On top of that, I cant really smell much of anything else to boot. (possible symptoms of sinusitus, <<<if thats possible ??) .

In the morning, and when I smoke, it gets really bad... My mouth gets really dry and I can taste it, and sort of smell it throughout the day, and if I dont eat something, itll make me feel sick...

In any inclosed area, car, room, anywhere, it doesnt go unnoticed by anyone, so its pretty bad, and its not like im imagining it.

So mainly my question is... If its not halitosis, and the problem isnt in my mouth too much, even though it feels like it is... What might be the causes of these symptoms, whether it be in my digestive system or elsewhere... Maybe if you could, list some tests, scans, ect , that I could take, that might help determine what it is exactly that I have.

Being a highly social person, I have trouble nowadays just having a conversation with someone, because its always on my mind, and I know if it was me on the receiving end, I would be offended.

If anyone has an opinion on this or some ideas that might help me/anyone else with these symptoms, please post a.S.A.P. , much thanks.