iOS 8 is coming tomorrow. (Hands in the air emoji!). Updates are great, but they're almost always buggy, which means you should back up your stuff before you load up the new platform. Here's a refresher on how.
- Make sure you're connected to Wi-Fi.
- Go to Setting. Select iCloud.
- Select Storage & Backup.
- Tap Back Up Now. Depending on the last time you backed up, this should only take a couple of minutes.
- Plug your phone in.
- Select iPhone tab on the top right-hand corner of iTunes
- Select the Summary tab.
- Scroll down to the second section. Under Manually Back Up and Restore, click Back Up Now. Then your computer will automatically begin storing all your stuff. Once again, this shouldn't take super long, unless of course you never back up your phone.
Once you're all set, upgrade at will. Have fun and good luck!