I am 18 and have two bald spots. I've never dyed my hair or anything like that, could stress be causing it?

Alopecia areata. Fungal infection of the scalp in adults is not terribly common. Based on your description this is likely alopecia areata. Stress if described in many patients with this problem. The exact cause, however, is not really clear. See a dermatologist to evaluate this. Often it resolves on its own but sometimes treatment is necessary to help it along.
Fungal infection. Your skin very likely has a fungal infection and should respond to oral anti-fungal medications.