Are you on an older iPad? CS uses lots of resources from your device. Check your usage in Settings for items using most of your memory. Move photos & videos to a computer since these take a majority of space especially if you use iCloud since you'll then have 2 copies of the same picture. Also, force close all apps running in the background, clear the cache in Safari, & delete any other apps you're not using.
Hopefully these will help you get the game loaded again.