Minecraft Pocket Edition Loading Bug

I must start out by saying that I have no idea what I'm doing right now, but I'd like to report an issue in my Minecraft Pocket Edition v 1.12.0. When I try to load a server, the game does not show the terrain, but instead it shows nothing but blue and a black sky. (Like if I was underneath the entire world) In the corner, it also shows that I'm underwater, but none of the bubbles disappear, or pop. Sometimes when I reload the screen I'll either move around like I'm hovering over the "ground" or I'll move in a very fast speed. And it's not like I'm running normally, it's like I'm running and someone is fast-forwarding it. I really hope this description explains the problem I'm having. But I have no idea how this bug report thing works. But thank you for reading my problem and I hope this helps