What sickness could I have where I can't stop sweating?

Last night, I woke up at four a.m., drenched in cold sweat. All day today, whether it was hot or cold, I was sweating. My ears started ringing, so I slept for a few hours this afternoon. Once again, I woke up drenched in sweat. I don't have a fever or anything, and I'm not generally a sweaty person. So what's going on here?