Apple ID won't verify.

My iPhone 6s had somehow signed me out of everything, including email, iCloud and apps. When I try to sign in to my Apple ID with the correct credentials, the phone just sits there. Once the screen goes to sleep, I get an alert asking me to sign in via Settings. I try it and it sits there again. It will not verify my credentials. I tried to do an update to my phone in the hopes that would solve some of the issues I am having but it won't verify the update. I cannot turn on iMessage to receive texts from my fellow iPhone users and every time I go to sign into email apps, I receive an alert to sign in to my Apple ID. My phone is pretty much useless. I've restarted it, I've refreshed it, I've ignored it and nothing has worked. I did go into diagnostics and found several entries over the past couple days that say "Bug Type". Did my phone contract a bug? What do I do? Any assistance with this would be so appreciated.