My IPhone 8 randomly turns off

I have had my IPhone 8 Plus (64 gb) for about 2 months. My software is up to date at iOS 11.2.6. My phone will have a small screen glitch, it will turn black and have some color streaks, turn off, and I will have to turn it back on. This will happen multiple times a day no matter what app I use. It also happens during phone calls which is annoying. My father and I got our phones at the same time, but his is fine. I have restored my phone and set it up as new, it worked for a couple days but it's starting to act out again. Someone help 😟