Working and 25 weeks pregnant

I work as a dental assistant and I am on my feet 8 hours a day 5 days a week assisting the doctor or running around grabbing patients. I am on my feet all day and the past couple of weeks having been suffering from bad sciatica pain in my lower back. I have an appointment with the chiropractor Friday which I hope helps, but am really considering letting my manager know I’m going to have to leave soon. By the time I come home I am just physically and mentally exhausted.... anyone else experiencing this or have gone through this before? 😔