help!

im almost 38 weeks pregnant and still working my ass off, im a vet tech so my job isnt easy im on my feet all day and up and off the floor. this past week has been extremely hard for me with back pain to the point i can't even walk when i get home after a 10 hour day all i do is cry on my way home every night this can't be healthy for the baby. they want me to work up until the baby is born my due date is august 10th. Will doctors give you a note taking you out of work for something like this??