I ran a large Sales and Marketing company whilst PG with DD, 9 years ago. It wasn't only mentally stressful, it was also very physically demanding. Lots of travel, 12 hour days in the field training new managers, followed by 3 hours in the office etc etc. I would have worked until I went into labour I think but DD was breach so had an ELCS. Worked until the day before I was due in, and was taking calls etc the morning of having her lol.
Went back to work when she was 3 weeks old whilst still EBF (I became an expert at expressing with one hand whilst on speaker phone and making notes) and carried on where I left off.
When she was about 3 months old I lost the plot lol. Left my job, the wanker I was living with (DD's father), left the house, my friends, everything. Came back home, lived with my mum and got a part time job in a pub.
I'm now 13+5 and this time I love being PG. I work from home on a very PT basis, have a sweetheart of a DP who earns enough to keep the 3, soon to be 4 of us and is adamant I will rest and enjoy this PG, and then the baby when he/she comes.
Its not always possible to just quit these jobs and I'm sure there must be a balance between what I did and carrying on the way I was doing BUT I don't for a second regret leaving everything and starting again.
I regret not doing it sooner and missing out on mat leave before DD came along, I regret missing those first few months together without any pressures and I regret that I didn't rest enough or eat enough whilst I was PG which I am 100% convinced contributed to DD being small (5lb 12oz) when she was born.
Your babies are babies for such a short time. And we get to be pg for such a short time as well. My advice is to enjoy every minute of both and make sure anything else takes a back seat, no matter what sacrifices you have to make.