IPhone 7 shutting down?

While switching between apps, my phone's screen suddenly turned black with the spinning circle you see when the battery dies. It's been doing this for 15 minutes, and it won't stop when I hold the power and home button at the same time. The phone is fairly new (bought four months ago) and hasn't been damaged at all. Help is appreciated.

Added (1). (It's completely unresponsive.)

It's been happening to mine recently because i haven't done the update which just came out, there's always an update with those freakin iphones it never ends, i can't do the update because i don't have enough storage, i deleted half of my photos and almost all apps and still not enough storage.
my guess is your phone is ready to be updated. Go to settings and see if there's a 1 next to updates and then run the update

wow i said update a lot haha