When I am in game I cant see the mobs drowned, phantoms, or spiders. I have tried to restart my game and have seen if there was something wrong with the seed but I can never see them.

I also cant see any of the chunks when I enter the nether but I can see fire and the zombie pigmen move around but I cant see any blocks.

Sometimes when I am playing all of the blocks will disappear and I can only see mobs.