I don't understand. I'm playing for 10 minutes, then all of a sudden it kicks me out.  It always says it bans me for 0 minutes because its trying to update the client. 
This is getting really annoying. I don't think i'm leveling up because I can never finish a match. Am I doing something wrong? Someone help!

Sounds like you might need to manually update PunkBuster.  This should help you out.
 
It happens from time to time.  It's one of the problems with PB.  Had it happen to me a week or two ago.

Maybe your a punk. Jk.

This happened to me before, Landon. Updating punkbuster is of course recommended, but you should look into turning off the Steam overlay active (the shift tab thing), you should try deactivating it on Steam > Settings > In-game tab > Deactivate "steam community in-game".
 
And yes, it's BS that punkbuster can't tell apart the Steam overlay from some see-through-walls overlay hack. If your problem wasn't even related to this, forgive me. :P

Punkbuster is, and will always be, shit.

Thanks. Hopefully this will work now.