Is your HUD missing? Well no thanks to Xbox support, or Mojang i will tell you what is wrong. The issue is a reset glitch. It put your look sensitivity down to 0, as well as unchecked half the settings! The most simple way to fix this, is by simply:
Scroll down to Help & Settings and press A.
Scroll down to Settings and press A.
Scroll down to Reset to Defaults and press A.
From there feel free to set things however you want them. And i hope this guide helps you out a lot!