intense lag, completely unplayable

realms is suddenly unplayable, there's only one person on the realm and no one else is on the whitelist. its only just new started doing this. the lag is causing ghost blocks that last for more then 10 seconds. eating takes 20 second and there's entire chunks that are glitched being completely dark with the mobs spinning in them. it does this for my other friends to and on there computers as well.