My phone keeps turning on and off by itself in a loop.

Hello, my mother bought me a Huawei P8 a little over two months ago. However, yesterday it shut down on its own and started turning on and off in a loop until it became usable again after 30 minutes. Today, my phone started doing that again, but this time it's been two hours as I'm writing...
Unlike a Samsung, I can't remove the battery from the phone whenever I want, so I have no "control" over the phone at that moment.
The phone hasn't suffered any drops, except from my bed.
I really don't know what to do. Has anyone encountered such a problem with a phone or maybe has an idea of what I could do? :/

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