iPhone backlight is fluttering and then the phone goes black.

The backlight on my iPhone 6s started faintly fluttering and then the entire phone screen went black. I tried to do the reset/restart by holding the home button and lock button down together, and nothing happened. i franticly was pushing the home button a bunch and still nothing. The phone then randomly came back (didnt restart) but just appeared normal again. Its done this now three times in the past 5 minutes. Battery is strong and ive pugged it in thinking thatd help? and nothing. please help! I just bought this phone maybe 3 months ago