I Have Low Grade Fevers 99.2 To 100.1 On And

I have low grade fevers 99.2 to 100.1 on and off several times during the early evening and late night only. I sometimes have night sweats as well. They always start around 4 PM or so and will go up down at will. I don't have them every day, it seems to be random. This started about 8 months ago, I've had several blood tests, including urinalysis and CAT scans that all have come up normal. What would be next course of action?