heater = cooler?

it's cold. the weird thing is that in the morning the vent above our room used to release warm air and now it is cold air. i do not understand why this is so. and not to mention it is 1:00 am in the morning and i have spent my entire night reading and making up questions. i'm so inefficient with my time. it's not good. i have a million other things to do and yet i feel like i'm wasting all my time. it's bad..