whenever i wake up in the morning, my mouth tastes horrible! it tastes like i haven't brushed in weeks, even though i just brushed the night before. and it takes a couple rounds of tooth brushing and gum chewing to get rid of the taste. this started maybe a month or two ago and it started as just if i didn't brush at night, my mouth tasted disgusting in the morning, but now it tastes gross in the morning no matter what. do you think it is a toothpaste issue? i use crest whitening herbal mint stuff but i've been using it for years. am i getting sick or something? this is really gross and i need some answers! thank you!