As a doctor told me, if you can't get motivated to study for the MCAT on your own, you might not be ready for med school.
I now agree with this line of rasoning, though I hate people who give that line, so I'll just say that you need to isolate yourself in the library. Just set aside several hours by yourself in the stacks. Bring food and coffee to stay awake. Once you get into a routine, you'll just be used to studying, and it won't seem so tedious.