When you wake up in the mornings , is your mouth extremely dry ?
I'm asking because i have had exactly what you are describing but with no blood.
I do have a severe snoring problem to where my tonge can actually be stuck at the roof of my mouth, mouth very dry.
I know my mucus is behind my uvula exactly as you are describing but like i said i have not had blood. i do smoke too, but if you keep seeing this blood, you may need to take a sample to your doc and see what's going on for sure.
Wish you well
BeHappy2