What can I do for my altitude illness without going to a doctor?

Safe descent. The best treatment for altitude illness or altitude sickness is to decrease one's elevation by at least 1000 ft (quickly and safely.) if symptoms do not improve, one needs to descend another 1000 ft. If one has symptoms of hace (high altitude cerebral edema) or hape (high altitude pulmonary edema) contact search and rescue and arrange for emergent air evacuation.
Altitude illness. Hydrate and get out of the high altitude.