My phone reset for no reason

[What3]

I went to turn on my Samsung Galaxy J5 and it powered off and back on which I thought was weird. Then when it powered on it said something along the lines of "verification incorrect, restart phone to reset to factory settings. This will erase all data." I tried turning it back off and on again to see if it would let me back on my phone as normal and it wouldn't let me so I was forced to reset my phone and I lost all apps, messages and photos. How can I get back the photos? They were stored onto my phone and I want to know if there's a way I can get them back. 

[AndrewL]

@What3: Sorry to hear that you have had issues with your Galaxy J5. Can you confirm if you manually created a backup of your personal data? If not, I recommend checking Google Photos, either on the phone itself (Apps > Google (folder) > Photos > Sign in with your Google account details), or on your home computer via the following link: https://www.google.com/photos/about/