Recent blood tests show im producing too many red blood cells. how bad is erythrocytosis? not a smoker. not at high elevation. have high blood pressure. generally fit?

I assume you don't have sleep apnea or chronic pulmonary disease. If only the red cells are elevated ( erthyrocytosis ) then chronic stress or excess testosterone are possible causes. If white blood cells& platelets are also elevated, a bone marrow disorder is likely & a hematologist should be consulted as a condition called polycythemia vera is suspected. In any event a hematologist can advise yo

Secondary polycythemia appears likely and work up directed by a hematologist will be needed. Gaisbock syndrome has typically the 2 features of polycythemia and hypertension and will have to be considered among others.

How much? What is your hemoglobin and RBC count? For info visit this site and see a doctor: https://www.nhs.uk/conditions/polycythaemia/#:~:text=Polycythaemia%2C%20also%20known%20as%20erythrocytosis,this%20sluggish%20flow%20of%20blood.