I think I acquired/caught/got a bad breath from kissing a guy. Is this possible?

Ok I kissed a guy(my first ever kiss unfortunately)..I deep-kissed him like an hour..I sucked his tongue, he did likewise..it was fun..after 2 days I noticed a foul smell in side my mouth (in my throat to be specific). So what I did is use a tongue cleaner immediately, flossed, gargle listerine with added hydrogen peroxide, brushed my teeth thoroughly...while using the tongue cleaner, I noticed a yellowish slime whenever I use tongue cleaner...Its been two months now, its still there..whenever I swallow my breath I can smell/taste it. I asked my sister and friend if I have a bad breath and they said I dont. But why do I smell/taste something foul coming from my throat? Could it be that I caught Epstein-Barr virus or some sort of STD? or did I develop a tongue/throat/mouth ulcer from over cleaning my tongue? I dont smoke either and Im a very hygienic person. What could it be?