How to wean baby while still co-sleeping?

I have to stop breastfeeding my 8 month old baby as soon as possible for medical reasons. I gave myself a deadline of 10 days from now and I am trying to get this guy to sleep without nursing and I absolutely cannot do it. He just cries and cries even if I’m holding / rocking him until I give him back the breast. He refuses all pacifiers. Usually we co-sleep for much of the night, but he is just constantly looking for my nipple. Any weaning tips for a co-sleeping mom?