The physical act of running may not be the most enjoyable thing to do, but I can think of a lot worse things to do; and even if you do not enjoy the act of running, there is no doubt in my mind you will feel better after.
Running releases endorphins, endorphins make you happy. So yes, you may have a miserable 30 minutes of actual running, but after that you will be in a better mood.
Not only will you be in a better mood, but you will also be improving your physical fitness. So now instead of doing your homework, you can be working for that body that you have always wanted. It is a win win situation!
So instead of studying for your physics test, why not go run?