tab 3

I attempted to send a gmail message with an attachment of a photo I had taken with the camera on my tablet itself. It seems now to be stuck in a loop saying "getting your messages" and it has been like this since Monday. Help please!

I have the Yoga3 on it's way, and looking at cases with an auto sleep/wake ike my Poetic case did for my Nexus 10. Few on Amazon.ca say they do, then in the reviews the customer comments say no, they don't. I can't seem to see if this tablet support wake/sleep function from a case? If so...