Phone not booting after OTA

So today I got an update for a new firmware, it was a small 125 mb patch, no big deal. I downloaded it and installed it a couple of hours later, I leave it to install and when I'm back my phone is frozen on the Motorola logo and the "Powered by android" text written below, but it won't get past that. I left it for almost an hour and it won't boot, I tried forcing a reboot and it gets me back to the same screen.
Is there any way I could fix it, preferably while keeping my data? Especially the what's app gallery.
Thanks a lot guys, I'm kinda panicking here.

Ps. I'm not rooted, everything is completely stock.