iPhone 6s won't let me sign into icloud, itunes, or app store

My phone started acting weird two days ago. Out of no where, it signed me out of all of my apps including instagram, youtube, etc. All of my contacts and notes were gone. My email accounts had all been signed out of. I can no longer use the app store or itunes store and I can no longer play music on the apple music app. I was going to try to restore my phone from a back up on my computer but it requires me to turn off find my iphone. When I went to settings to do so it prompted me to sign in using my apple id. After attempting to sign it, it just asks me to sign in again and again. So I can no longer access anything in icloud. It does show me how much storage I have in icloud but it says "Zero KB of Zero KB Used" when I should have 50 GB. There's also a message under it that says "Unable to load Storage Info". So I close settings and reopen it and notification pops up telling me to update my apple id settings, but again, it prompts me to sign in which doesn't work. I figured it was my password but I've changed it twice since and it still isn't working. Any solutions?