Hi guys I'm freaking out! I was in the middle of doing my assignment when my MBP suddenly restarted itself and now it's stuck on the start up screen with the Apple logo and a progress bar, which hasn't moved in hours. And the whole thing is badly pixelated for some reason. I have no idea what to do and I'm scared I'll lose my data as it's not backed up (stupid, I know). Please help me, any advice would be highly appreciated! Thank you.