I wake up with blood and bloody phlegm in my mouth every morning. It tends to be accompanied by a sore throat. Been going on 3+ weeks. See a doctor?

See a doctor . Blood on the phlegm and sore throat can signs of irritation, infection, or allergy. See your physician ASAP. .
Seasonal allergies. Most of the blood comes from the area inside the nostril, which is where most of the blood vessels in the nose are located. can cause the mucous membranes in your nose and mouth to dry out, and this can facilitate nose bleeding. A small amount of blood in your phlegm is nothing to worry about, but if you're seeing large volumes of it, call your primary care physician for investigation.