It gets so hot in my room at night!?

This has been happening for the past 2 days, for some reason, when it gets about 7 or 8 o'clock it get REALLY hot in my room. It just turned May in Indiana, so it can't be that hot. It's pretty chilly outside and in all the other rooms. I leave my computer on but I put it on sleep, and I think that is causing it, but I don't leave on any lights and almost every window in the house is open.I also have a basement but it is still hot too. Please help. It's 8 right not and I'm sweating like crazy.