I need to stop being a pacifier overnight?

Seriously. No judgement. I really need the non-nutrition based overnight feedings to stop. My daughter is waking up 3 times a night out of habit and refused to go back to sleep without nursing. Now I used to be able to handle 5-6 hours of broken sleep with a pot of coffee, but I'm pregnant again and I feel like I need 18 hours of uninterrupted sleep. I've tried cosleeping, she crawls out of bed even if she's still tired. I've tried throwing a mattress down on the floor and sleeping there, this worked for a while but isn't anymore. Anyone have ideas? She's 15 months and nursing 7-8 times a day, I want to keep nursing through the pregnancy, but I can't keep doing 3 nighttime feedings anymore.