iPhone not restoring from backup?

Currently, I have an iPhone 5S, running iOS 8.4. iTunes is version 12.2. Whenever I try to restore my iPhone from a backup, its not completing. It gets stuck at the halfway point, every single time I've attempted. I've tried 4 times, and it gets stuck at the halfway point, and it says 48 minutes remaining, 1 hour, 2 hours, and eventually 5 hours remaining. I'm wondering if this is just me, or if it's happening to everyone. I've used 23 GB of the 32 GB iPhone, so is that a contributing factor to the problem? Even left on overnight, it still is stuck at halfway. I really hope this can be fixed, because now I'm left with an iPhone, that has literally nothing on it. Thanks, I really hope you can help. 🙂