Maternity leave woes

I’m 10 weeks pregnant and trying to plan ahead because I’m a teacher and due on the first day of school (horrible timing, I know). I live in upstate New York, so I was reading about the NY state maternity leave policies and looking forward to having some paid time off with my baby. But when I met with my HR director, she informed me that our teachers union had opted out of the public maternity leave benefits and created our own plan. I was absolutely devastated to learn that my school only offers 4 weeks paid maternity leave. I know that some people don’t even get a maternity leave and I should be grateful. But 4 weeks feels like such little time. The only solution my HR director offered was to apply for 12 additional weeks of unpaid family leave after my 4 weeks are up. I’ll probably end up doing that and then just quitting my job and finding a new one. I’m so frustrated and I feel so spiteful about their lack of care for mothers. Has anyone experienced anything like this?