Fan Running Until My Mac Dies

I have noticed my fan being much more active lately. So much to the point that whenever I put it in my backpack, I can hear it aggressively venting non stop. It has gotten to the point where it is overheating itself by venting. I leave very little apps running, and don't do anything taxing on the computer these days, just Chrome, Messages, and Notes. I close all my tabs before closing up my laptop and putting it in my bag for the night, but everyday I have to charge it from dead before using it because it vented itself to death. I'm not sure what is causing it to do this. Any ideas?