I had about 48 hours of audio hallucinations on and off with the bug I have.The third,"bad" day,I was even having visual hallucinations.
I had a slight fever if any and have never used illicit drugs.Another FReeper had hallucinations back in the 50s,I believe with flu.
Have you heard of this before without a bad fever?
I'm not an MD, but when I hear hallucinations, I think of encephalitis. I think you should give your MD a call and get a professional opinion.