High risk and work....

I'd take it to some one higher . If not threaten to sue them

I'm so sorry that's happening to you. is there someone from HR you can contact?

This is a violation of the pregnant workers fairness act.

https://www.eeoc.gov/wysk/what-you-should-know-about-pregnant-workers-fairness-act

Please read this, and talk to your employer’s HR department about their process on ensuring you have an official accommodation on file.

That's messed up if anything happens to you or your baby I would sue them for shore

I’m sorry but you must legally take action.

You need to do possibly FMLA or some how do L&I /: I’m not entirely sure but there should be laws to protect you /:

There are many laws that protect you, but you must take documented action on making attempts to get accommodations officially logged with your employer. Please visit the site for the eeoc and speak with your company’s HR department about getting your weight lifting restriction on file and document every time your boss attempts to violate it. I would suggest having the voice recorder on your phone going whenever you’re there