Welcome to the forum Tyler.
It could be the battery - sulphation can cause the cells to short out and rapidly drain themselves. The trick here is to put a multimeter into Amps mode, take the positive lead off your battery (with everything in the car turned off), put the red lead of the multimeter onto the positive terminal of the battery and the black lead onto the wire you just removed. With everything turned off, you shouldn't see much current being used at all. There might be some used for the car alarm, stereo in standby, UHF radio if it's not on an accessories circuit etc, but these should be standby amounts - it should be a small part of an amp. If it's anything over 1A, something in your car is using power when the car is off and you need to find it! Is there a second battery in the back?