When did you go on leave?

I work full time, on my feet most of the day. On days when I start at 730 am I find myself tired around 12pm. Some days I start at 5am. I wanna work my whole pregnancy or atleast until July 1st (due July 19th). When I get home I just sleep, and days off I catch up on housework. For Women who already had babies how long did you work? and what kind of work do you do? Am I aiming to high trying to work all the way to the end? Was it difficult working in your last trimester?