Yes. Any infection can spread through the blood stream and be life threatening, especially in this age of antibiotic resistance. Don't play russian roulette, got it treated.
Rare, but yes. Before antibiotics, a tooth abscess was one of the leading causes of death. Obviously antibiotics help in treating infections, but an abscess that breaks into your bloodstream can quickly spread to other parts of your body, tax your immune system, and send you into septic shock. At that point all the antibiotics in the world may not help. Get the abscess treated.
See any dentist. to drain the dental abscess. If not treated, a serious dental abscess can eventually kill. The infection may spread to your jaw, cheeks, sinus and to other areas of your head and neck. It is very common to feel poorly with spreading infection. See any dentist for examination, x-rays and treatment.