With my first I worked at an assisted living and worked right up until the day before she was born. I work as a cna in home care this pregnancy and I'll be working right up until I have this little guy.
I say don't push yourself. I worked up until today 38 weeks 5day and truly was unhappy and uncomfortable for this whole week. I let my convince me to stay much longer than I would have liked.
I to am a cna, i work in a nursing home. I take care of war vets and they are big men. Out took allot out of me but i managed. You are allowed as many sit down moments as you want. Of course work must get done in between. Anyways, i worked up to 36 weeks n only bc i gave birth. (worked friday, baby shower sat, labor sun, n baby 12 am monday) i didnt have much time so i went back after seven weeks. But this pregnancy i couldnt do that. Im on bed rest from 8 weeks. Anyway. Work up till you cant work nomore n give a two week notice. But things happen. Good luck