CNA and Pregnant

So I'm 22 weeks pregnant and my job is aware of me being pregnant but they don't seem to be very considerate a few of the other CNAS didn't mind switching the more heavier patients with my but my job says if I needed to be in light duty I had to get a note from my doctor but they don't do light duty so I'll have to take my maternity leave. I don't need to be on light duty just switch the heavier patients if my coworkers don't mind I don't see the issue I'm so frustrated because it's so tiring my feet are starting to hurt and their always rushing I can't work like I used to but I don't know what to do I have to stick it out for at least another 14 weeks because I need my job