Maternity leave at 37 weeks

Is it too earlier to take off work?I'm about to be 37 weeks on Friday and would like it to be my last day of work. My original plan was to work until the 21st,but i dont know if I can make it another full week. I am just so exhausted and dealing with sciatica problems and numb hands all day due to carpal tunnel. I dont know much about California maternity leave since ive seen several different doctors this pregnancy and all of them are telling me something different. Is there a difference between taking time off before the baby is born and taking time off after the baby is born? I dont want to take time off before the baby is born if its going to cut down the time i get with the baby?