IPhone 6s screen cracks for no reason?

I got this iPhone for my 18th birthday not even two months ago, and it's already cracked all over. I had a screen protector on by just took it off to see f these cracks were superficial or not. I was sitting on the ground for not even 20 mins and I fell asleep. Woke up and t was cracked all over. I'm by myself. No one has been around besides my mom over two hours ago and my doors are locked so no one came in and dropped it randomly. Anyone have any ideas?

Not sure what to tell you, seems like your body pushed the phone into the ground creating pressure on the screen causing it to crack. Always have the screen facing your leg so that your leg is pressing against it rather than hard objects. If you ever bump your leg with your phone in your pocket it's less likely to damage the screen and phone as well.

It typically costs $100 to have a new screen installed.

You probably rolled around and crushed most likely.