iPhone 6s resets entirely.

I've had this issue a couple of times, just out of the blue when I'm not doing anything and I grab my phone to look at something it shows me a iTunes logo with www.support.apple.com/iphone/restore

I then have to reset my phone to factory settings which means I lose everything on it. Any advice from anyone? 

sounds like you went into restore mode

saving all your data and doing a factory reset will outrule any software issues, if the issue persist it's a hardware issue, and will most likely be linked to home and power button

It’s highly possible that most of your data is safely backed up either on iCloud or on your computer via iTunes. What it shows you is basically called DFU or restore mode, whatever you wanna call it and it shows that you’ve somehow bricked your phone. 

From my experience there is not much you can do besides of fully restoring your device and the setting it up from the backup I’ve previously mentioned. @John Woll

You can save your data on the Itunes from your PC. And you can reset your phone. I suggest you to do that because, it's better for your phone.