Have you just recently updated your operating system to iOS7 and or accessing your Gmail account? If you have, I've been hearing in person and online that there are many bugs needing to be worked out on the new iOS platform, including Google powered apps and systems. Beta is having many issues overall with support to many applications. Yes, there are a few lucky ones that do not or have not run into any problems, but despite this many apple users are finding out that the new iOS7 platform is just not up to par yet. Specifically pertaining to Google, Apple devices are seeing apps crash even on re-install. I believe Apple is actively working on support for Google. If this is the case, then the best thing you can do is to keep posted on iOS7's updates and hope that they resolve the issue quickly. Look for some type of support for your emails or try a third party email app that may have support and access your account from there. Hopefully this helps!
Ben
Lead AV Tech, Edited by Moderator - do not promote your business here, please read the forum rules