Advice on how to quit breastfeeding!

hi! I’m looking for advice on best way to stop breastfeeding WITHOUT causing engorgement or mastitis. I plan on calling my doctor on Monday but I got a shot today at a walk in clinic that will dry up my milk so I’m not sure if i need to abruptly stop pumping or gradually stop. I exclusively pump-- I don’t nurse at all. My son is 5 months & is already supplementing half of each feeding with formula. The walk in clinic nurse said she thinks I need to just wrap up with ace bandage & don’t pump anymore at all but she said she is not a specialist so she isn’t sure. I’m so scared to get engorged or end up with mastitis! please help!