Parts of my world will not load into the game

ill load my game, and ill be using my command blocks to tp to other parts, and they won't load and it will be really glitched, as in I can't use any buttons to get back to the main spawn area. it looks as if the world didn't load in on that part, but it never actually loads, so I have to restart the level. It gets annoying and it would be appreciated if you could fix it