I'm an OR/Recovery Room Nurse, and I'm facing a similar dilemma. If your work offers you the ability to work in triage, I suppose that sort of counts as "light duty" in comparison to working in a pod, so if your OB requests modified duties for you I'd hope they'd be considerate enough to put you in there.
At my work we had a nurse who required modified duties at around 32 weeks or so, and she had to go on short term disability because our unit couldn't accommodate her. I'm just about 18 weeks along, and can barely move lately without crazy hip/leg pain and cramping, so I'm worried I'll soon face the same fate.
I sincerely hope you're able to get some modified duties at work if that's what is required, but at the same time I understand the amount of work even a triage nurse has to do, and if you're having such difficulties even performing basic activities without problem it might be better to be off work for awhile.
FX for a good appointment on Thursday! Are you hoping for some modified duties?