You have to enter no substrate mode on your phone, it means that your phone will be jailbroken but you cant use the jailbroken apps, after you go in no substrate mode, find gameguardian and delete it if you are sure that it is the last thing youve downloaded to make it do that you have to delete it. (Ps if you suspice that other tweaks or jb apps could be the reason why also delete it) after that just re-jailbreak your phone and everything should be back to normal after you've deleted the app thats causing it.
Here's how to enter no substrate mode:
http://www.idownloadblog.com/2017/02/03/how-to-enter-no-substrate-mode-ios-10/