I would just go on disability not quit yet
As long as you’ve paid into SDI on your paychecks within the last 18 months you’re eligible for SDI (4 weeks before +6 or 8 weeks after depending on type of birth) & PFL (8 weeks that have to be used within 12 months of birth). I was a contractor so I technically quit my job when I went on disability before giving birth. Also, if you’re having any signs of PPA/PPD/other complications be sure to tell your OB & you can get your disability extended. You have to ask them & they can do it.
Also keep in mind, to have SDI you need to have worked the last 18+ months
Your employer clearly discriminated against you, based on pregnancy. You can sue them. In my experience, EDD talked to me and asked for documents from my employer. But you know what? You can try , and if you are denied, you didn’t lose anything.