Voice is an octave lower, I have a fever, but no cough or other real symptoms?

Laryngitis. This sounds like a viral laryngitis. I presume that you might have a sore throat with low grade temp and possibly some post-nasal drainage. A deep barking cough may develop as well. As long as symptoms are "low grade" symptomatic treatment with tylenol/motrin and hydration will be all that is needed. If your voice symptoms persist beyond 10 days, a course of steroids would be helpful.
Fever/voice change. Is this a sudden illness or have you been experiencing this for a long time. Prolonged fever with no know cause always requires a complete examination with your physician. The voice change may also be significant.