If i sleep in fetal position only, my saliva flows from my mouth that stains my pillow a litttle brown. but i do not seebloodinmymouthwhat is this?

Probably blood: For blood to tinge your saliva and thus stain your pillow slightly brown, not a lot of blood is required. It could be a sign you have gum disease and during the night you grind which causes slight blood seepage around the teeth and leads to the stained pillow. Your saliva would dilute the blood so it wouldn't be readily visible in your mouth. There may be another cause, however.