Waking up with blood in my mouth?

See dentist. When was your last dental visit and teeth cleaning. The most common reasons for bleeding in the mouth is periodontal or gum disease or infections. See a dentist for an exam and treatment. This is a problem that needs to be treated, it will only get worse without treatment.
Gum disease. Bleeding gums can be a sign that you are at risk for, or already have, gum disease. The bacteria, along with mucus and other particles, constantly form a sticky, colorless toxic “plaque” on teeth causing the gums to become inflamed and to easily bleed. Bleeding may be a sign of a serious problem, which should be checked by a dentist. It is a painless condition, but can induce serious complication.
Possible gum Dx. There are some possible causes that will make bleeding in mouth. Gum disease in one of them and very common. You should contact a dentist first for any oralfacial problem.
Bleeding. Any abnormal bleeding should be investigated. Start with your Dentist. You may have a dental (probably periodontal) problem that requires attention. If the cause of the bleeding does not have a dental origin, your dentist will refer you on to your physician.