So before I started my car up to leave work and all my interior lights were off. I open the door and turn the car on and the right light turned off, but the left stayed on the whole drive home. What would be causing this and how can I stop it so my battery won't die over night?

 

Not sure what light you are talking about. Door light? Or top interior lights? Check the door pressure sensor. Its like a little rubber push pin about half the size of your pinky next to the drivers seat, on the door frame/chassis.
There is a screw by it if I'm not mistaken, that adjusts the amount of pressure it can hold. Check it out And be more specific on the light.