Hello my ipad 3 is not updating or downloading new or already purchased apps

I have rebooted the ipad, backed it up over wifi and on my pc. Have even downloaded and SEEN apps copy over through iTunes onto my ipad only for them not to be there!!! I have checked all my apps and none are paused or awaiting download. I have logged out of my account and back in. I keep clicking on icloud download icons for apps I've already purchased but NOTHING happens, no message, nada, zip!!! Please help me from going insane.

(PS my iphone 4 can still download/update apps fine?!)