baby with cold hands

For the last 07 hours my baby's hands are continuously cold, really cold, as well as her face. Her room temperature is 75 F, and she's wearing two layers of clothes. I don't let her keep a wet nappy and when I change her the body (arms/legs/trunk) is not cold. Any ideas on what is happening? Before today I always considered cold hands a sign of cold in general and would layer up or increase the heater and it would work. But today it isn't working...