A 21 month old with Night Sweats?

My 21 month old daughter has been waking up every night around 2AM screaming and crying! She is soaked from sweat and does not want to lay back down in bed. She sleeps with nothing but a pair of pj pants or shorts and a fan pointed right on her. We live in Florida so the A/C is also always on! I have no idea why she sweats so much and is waking up in the middle of night crying. She never used to do this it's been going on now for almost a month. Does she have Night Sweats or what can be the reason for this? I am going to get her into the Dr. But Id like some idea as to what to ask about.