What was happening to me?

Today, me and some friends do p90x everyday after work in a warehouse, I drank a lot of water and ate my healthy meals during the day. But for some reason during halfway my workout, I started getting nauseated and started getting chills in diffrent parts of my body especially my head. After I felt like if I was in shock, couldn't think straight and was getting goosebumps. I have the feeling that it was a huge *** fan we had turned on blowing right at us the whole time. Was it the fan?? Was I fainting?? Hypothermia? Texas weather?