My MacBook Pro is not sleeping when I close the lid on battery

I purchased my macbook back in 2011, and this problem just started. When I unplug and close my computer to put it in my backpack for school, it does not sleep. I take it out and its very hot and has lost a large amount of battery. My energy saver controls say it should sleep after 10 minutes of inactivity, but either way it should sleep when I close the lid. I don't have any sharing options checked or any running apps that should be keeping it awake so I have no idea what could be causing this

Have a look at this answer which indicates the commands to help you analyse if any process is blocking the sleep of your MacBook.
If nothing is blocking it, then look at :
```
egrep -i 'sleep|wake' /var/log/kernel.log
```
and look if you see a sleep line at the time you close the lid. If you don't, look at any information message in:
```
/var/log/kernel.log
```
around the instant this event should have happened.
Create a test account, close your session, and open one with this test account. Is your MacBook entering sleep when you close the lid?