Why does my Phone keep turning itself off and then back on?

My phone is a Samsung Galaxy J1. I can't find any reason for it.... I will be looking at Instagram posts or talking on snap chat and then it will just turn off and then turn back on all on its own. and sometimes when it turns on, it gets stuck on the Verizon screen and the only thing i can do is take the battery out... is this a bad idea? other things at have been happening lately that might have something to do with it are that it has been really slow lately and sometimes it dies when it is still pretty far from 0%

If anyone might know what is wrong and how I can fix it, please help. Thank you!