Gameplay is Glitchy

Put the summary of the bug you're having here

I have had Minecraft Realms for several months and had no problems. Then when 1.12 was downloaded I started having issues with lag time. These problems tend to increase with more users in the realm. I have played a game in version 1.12 Minecraft and did not have any of these issues.

I expected to have smooth gameplay. When running moving forward smoothly. When attacking monsters smooth gameplay where I can shoot them with an arrow or swing a sword seamlessly. When mining blocks, being able to clear large amounts of blocks without difficulty.

What actually happens is when I run or move forward some times I will move forward several spaces an then all of the sudden I will be brought a few. I even had it where I was moving in a boat, got to my destination, got out of the boat, walked forward, and all the sudden was back in the boat away from the shore.

When I shoot an arrow sometimes I hit the attack button and nothing happens for several seconds then I either hit it or don't as the mobs move very choppy. When I attack with a sword I can hit it but due to the pauses in gameplay it sometimes results in me getting damaged.

When I try to mine blocks, sometimes I have issues with blocks getting mined and reappearing.

All these this seem to intensify when I have multiple users on at the same time. I have tried to decrease these problems by lowering the gameplay setting to increase fps. I got up to 120 fps and still had the same problems.

I believe all these glitches are symptoms of the same problem. I also realize that my problem is similar to problems that other users are having. Please let me know if you have any questions or you can do anything.