Why do i have green to brown coating on my tongue and roof of my mouth every morning? it tastes bad. i'm very thirsty. i have blood speckled mucus.

Morning breath: If you're thirsty when you wake up - you're undoubtedly dehydrated (which happens normally after not drinking for 8 hrs or so) - perhaps you're a little 'drier' than you should be? And, you're likely mouth breathing so the natural, germ fighting saliva dries out. Perhaps too medicines have an effect like antihistamines for allergy. Smoking of course wouldn't help and some foods can lead to odors.