Hi ladies another question

I have a full time office job at the moment, i am working 8:30 til 5:00. i was wondering how long b4 bubs arrived did others in my position stop work?
My job isnt exactly stressfull but can be very hectic at times, i spend alot of time on my bum but that can also be uncomfortable. I am getting rather big and i only have energy until about lunch time. I cant go on to part time either just full time til mat leave starts. I am planning on finishing about 8weeks b4 because that will bring me up to the first week of Jan. Its just other ladies i know have been working til about 3weeks b4..... i know everyone is diff. Just want some idea on what everyone else is doing.