Troubles with my Samsung Galaxy S5? I don't know where else to turn?

Yesterday morning, everything was running fine, all apps were opening, I even installed a new app. When I got out of class, I attempted to open an app I use frequently, Snapchat, and it was stuck on loading. I thought this was just a bug and attempted to fix it by deleting the app and reinstalling it. However, when I went back into the Google Play Store, I got an error that read, Check your connection and try again. I've tried everything from Clearing the Play Store's cache, Syncing my Google accounts, nothing works. Please, if you know how to solve this problem, say something below. This problem is really bothering me and I haven't a clue on how to solve it.

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