My health, inventory, armor bar and chat all dissapear.

When i dont press on my inventory (the 9 slots you see when your playing) my health, the 9 inventory slots, my armour bar, the chat, the chat button (so i can chat) and the Home button (this one: ⏸) all dissapear, and when i do press on my inventory, i can only see the things for a few seconds. I love the game and i hope you can fix this, cuz now i cant really play it, i need to see the things.