Any tips/links/books for gentle night weaning

I don’t need to wean ALL night but going from 11 feedings overnight to 1-2 would be really nice. He’s 18 months now, I’m pregnant with #4 and very sick. Being up all night to nurse is just exhausting and I’m getting angry when I shouldn’t be. Neither of us are getting any rest at all. He was doing great sleeping at night until about a week ago so I’m assuming this is the 18 month sleep regression. I also know I won’t be able to handle nursing TWO kids all night long. Adding another nursling to our current night schedule could literally kill me 🤪