Stress during pregnancy is not ideal for you or baby. But you know what? Stressing about whether your stress is stressing your baby....? = more stress.

You know that you're anxious, you know it feels rubbish and that it's something that you want to work on. That's enough. Just keep on taking baby steps to take care of yourself, to address your worries, to unwind and remove pressures where you can, and you, your little guy and your bub will benefit. Huuuuge hugs. Anxiety sucks.
This is almost exactly what I was going to say - nine months of stressing about whether stress might harm your baby is risking a self fulfilling prophesy.

Focus on becoming one with the zen, and (more practically) figuring out who can get stuff delegated to them.

Can someone else do the shopping? Can someone pay for home delivery? Can someone else mind DS while you do it?

What tasks are unavoidable and on your list ... who can help out? What can wait? What can be vetoed?

What self soothing things can you do to help yourself be calmer? I know the "everything has hit the fan and I am about to burst into flames" thing - if that's where you're at, you need some strategies for bringing yourself back down - and maybe some strategies for helping DS back down too ... maybe some ladies here have some suggestions

Personally, I find a quick walk, a sudoku or three, screaming into my pillow for a bit, or a 10 minute vent in confidence is great.

My only magical cure for a DS about to rub my last hair the wrong way is 15 minutes of TV, playdoh, the park or a banana ... I'm guessing 7yo and 2yo are different, though

Good luck, hun