my game buggibg before the baby update

so when im try play minecraft, before the update far from update,everything fine i can run and other,but after the update (before update the baby animal or the tag),my game sudden change,sometime when im play world the sky diffrent,its like have an error and black sudden then back to normal light,then i cant run.i try to click shift not working or click double w still not work,i try see and change nothing work. can you help me with this and the game super lag when im try to walk away from zombie or other entities who can attack us in the game and the game sudden frozed and i die because of it like it already predict my death