i do everything i could think of to prevent bad breath. for ex- i brush my teeth twice a day, use mouth wash at LEAST twice a day, and chew mint gum whenever i get a chance, yet my bf says that my breath smells like "helium or something, it has for 11 months" he said he notices it more when im on my period, but how would they relate? PLEASE HELP!. anymore suggestions?
i also brush my tounge and sometimes the inside of my cheeks

My doctor told me that if you have "internal" bad breath, all those things are going to do is mask it. It's actually the smells from your stomach acids overnight (because your mouth's closed) building up, and that's why it's worse in the morning. You might also be unlucky and have Halitosis*.

* – http://en.wikipedia.org/wiki/Halitosis