Weaning baby help

My son refuses to wean. We’ve gotten him down to 3 nursing sessions left but he won’t let us drop any more. He is now waking up at 4 AM everyday screaming until I nurse him. He wont drink from a sippy cup, won’t eat a snack, nothing. Even rocking he just screams. Nothing makes him stop until I breastfeed him. How can I encourage him to be done?