When to take off work when pregnant?

I'm 30 weeks today (with my first) and I work in a dog boarding and grooming facility. I take the dogs out 3 times a day, which does mean I get yanked around a lot, there are a lot of up and down stairs at my job too. I literally trek up and down at least 60 times a day. I bathe dogs, clean up feces, and then do a lot of miscellaneous work. Im going to talk to my doctor Wednesday when I should take off work but would like other thoughts and opinions before hand. Thanks!