Welcome to the Apple Support Communities, I know how important your iPhone 7 is to you, so let me help you getting this issue resolved. Since you said you updated to iOS 11.1.1 (15B150) yesterday, and now you are having these issues, your iPhone may have had an issue installing iOS 11.1.1.
1) Restart your iPhone 7 Plus: Restart your iPhone, iPad, or iPod touch - Apple Support
2) Restore your device to iOS 11.1.1 using iTunes for macOS or Windows, Before attempting this step, back-up your iPhone using an encrypted backup so all Health data, and Activity data won't be lost (especially if you use an Apple Watch) if you don't have a computer, set up an appointment with Apple Support.
3) In iTunes with your device connected using your Lightning Cable, in the Summary Tab click "Encrypt Backup" and click "Back Up Now" wait for the process to finish, then on your iPhone, navigate to Settings > [your name] > iCloud > Find My iPhone and turn it off, if you don't turn it off your device will go into Activation Lock mode.
4) On your computer, in the Summary tab, click "Restore iPhone" your computer will Download iOS 11.1.1 from the iOS Software Update Server, then will restore your device to iOS 11.1.1. Do not disconnect your iPhone during the process, and leave computer connected to Internet at all times.
5) On the Summary Page, if prompted enter in Apple ID & Password, then set up your device. When your iPhone says "Set up As new iPhone" etc, click "Restore from iTunes backup and follow the prompts"
6) Then, click "Restore Backup", select the latest backup and click Restore.
As always, if you need more help, please reply to this post and I will be more than happy to help you out.