Lag and chunk loading

When i go through either a nether portal or the end portal, it lags a lot and the chunks won't load at all. Even when i try F3+A (Reaload chunks) it still won't load. I am also unable to pick up items and the game is genearally very laggy. I have to exit and re-enter the world for it to work. This is very annoying, and especially affects me since i dry sponges in the nether a lot, since i'm draining an ocean. The image attached puts the bug at full display.