When to take maternity leave?

I’m 37 weeks 2 days and at work I’m constantly on my feet and bending and lifting.. I’m exhausted after a couple hours.. I’ve tried working less but after 2-3 hours I’m so soar and my feet are always swollen.. I don’t get paid maternity leave and not sure if I plan on going back to this job after I have the baby.. when did y’all take leave or what helped if you had a job where you were on your feet 8+ hours a day..