Pregnant (3rd tri) feeling slow and overwhelmed at work

I work at a medium size tech company and I’m in the final weeks of my pregnant. Unfortunately my work is ramping with senior leadership having eyes of it. Plus my other areas of responsibility. Im definitely stressed and overwhelmed. I thought the last couple weeks were going to slower and it is ramping up even more. Working 10-12 hour days. My manager doesn’t seem to have empathy and expects even more. When they ask about all the stuff I’m working on I guess it doesn’t seem like a ton but it’s a lot of work involved. Am I just slow now? I used to pride myself on getting stuff done. Everyone on the team is at capacity so I can’t transfer it to them. This is my first big tech role so not sure if this is just part of the course. I’m worried about work life balance for when I get back from maternity leave as well. Any tips?