Could You Possibly Tell Me Why All Of A Sudden

Could you possibly tell me why all of a sudden I got chills in a 87 degree public pool while I was doing a regular nightly exercise program. I had been going to the pool at night doing light swimming and light water aerobics I stopped to have a brief conversation with my friend in breast deep water and i felt chills all through my body. I thought noting about it and it happened again with-in the remaining time I was in the water. I got out and I haven't been back.