WFH and HL

Context: I'm about to be in my week 37, and I'm already WFH. My gynae will give me HL during my next appointment. However, I have a concern that my boss may ask me to continue to work despite having HL since it's just switching on my laptop and clearing some work to her. How should I let my boss know that it's not just about that, but I need to relax my mind before I'll pop anytime soon #advice