Syncing with gmail and iCloud across 3 devices

I cannot get my devices to sync properly (MacBook, iPad mini, iPhone 5c). I use Gmail and iCloud, and it seems to muddy the waters. My contacts, for example, are a mess. As someone who is normally on top of the tech stuff, I feel confused and very frustrated. Is it time to get rid of Gmail? Do I need to wipe my data and start fresh? For some reason there just seem to be too many settings to get everything to work seamlessly. If anyone has faced similar issues please let me know if you have any solutions--whether it is a step by step process, or visit or the Genius Bar...

Thanks!