Boss won't let me go on leave early

Kaischa
Im 35.3 weeks pregnant and I work in a hospital 12 hour shifts. I am always super stressed out from work and exhausted. I gave my boss notice saying that I'm going to leave starting on July 9th (38.3 weeks pregnant). Well she came up to me and was asking why I wanted to leave early since my due date Isn't until July 20th and that she's going to continue to schedule me until July 23rd. I'm not one of those mommas who want to work up until my due date I want time to rest and get ready before the baby comes. I'm just so frustrated that I'm not being taken seriously. I don't plan on going back to work there after the baby, but I don't want to just quit on them because I would like I good job reference. I just don't know what to do