IDK what the laws are where you live but here in Illinois employers are required by the state to accommodate pregnant employees or allow them Dr mandated leave.
Just remember they can't well their not suppose to penalize you unless they want a law suit for working you all crazy.
Go to work and do what you can. That's what I did. They kept giving me crazy shifts and task with bending over. I did what I can and went on about my business. Lol they soon caught on tho cause they started checking on me gave me a chair and didn't dare look at my sideways when I skipped over doing certain things. And the hospital of all places should sympathize with you ! I just took my maternity leave last Monday and I'm due on the 2nd and I was a hot mess always passing out , walking off to go to the rest room lol .So stay on their clock and only do what you feel comfortable doing.
Your job is obligated to give you light duty if it's doctor's orders. If they can't accommodate that, then you're required to go on leave early but they can't penalize you for that. Just talk to your doctor and let her know what's going on and see if she'll put you on light duty