Loading, freezing, restart, repeat

So once in a while for the past few months I've been getting a random black screen with a loading symbol and it would do that for a few minutes and then go to my lock screen but now it's stuck doing it over and over. Even after the phone reboots by itself or I have to make it reboot,

Every single time It turns on and I try to unlock it, it unlocks for just one second and most of my apps are gone for some reason but then, my screen goes black pretty immediately with that loading symbol but the symbol freezes now after just a second of spinning and doesn't spin anymore. It stays stuck like this for a really long time before it finally reboots itself or I make it reboot and it takes a super long time to come on and then when I unlock it after its finally back on it just happens again anyways. It hasn't let me unlock it for 2 days and has been doing this over and over. Tried charging it and rebooting it a million times and I just got icloud storage like an hour before this started so I could back up my photos of my kids and now I can't even get into the phone to get it to back up. I don't want to have to reset it and lose all of my pictures that are sentimental to me that I wouldn't ever get back. What can I do to make it back up my photos or make it stop freezing and crashing. Also I don't have a computer other than my Chromebook so that's not an option