Sciatica when pregnant

I'm 28 weeks pregnant and been suffering with sciatica quite bad my job is physically demanding and causes me a lot of pain toward the end of my 8hr shift. But it's recently got worse as pains in my Leg causes my leg to give way and last night I fell because it it straight onto my back where I get the pain and it's bad it seriously worse I can barely walk or sit down comfortably. Anybody suffered with this and what did they do to ease the pain? I have a great fiancé who helps me walk and even get dressed but he can't be there all the time. Paracetamol do not have any affect what so ever. Laying down doesn't work cause ing aching in my buttock and leg too x