Minecraft overload??

Evert time i play the launcher says :
<<[12:29:25 INFO]: Client> [12:29:25] [Server thread/WARN]: Can't keep up! Did the system time change, or is the server overloaded? Running 2019ms behind, skipping 40 tick(s)>>and it lags a lot!!!!!!also when i spawn/summon a rabbit the launcher says cant play minecraft:mob.rabbit.hop
""PS im playing on a singleplayer world""