Work accommodations?

J
I'm at a point where I know I need to ask for accommodations at work. If anyone remembers, my boss has been terrible the entire pregnancy so far (complaining about the number of times I need to use the bathroom, saying how I have an excessive unnecessary number of appointments, and just generally being an ass) to the point where I had to get a note from my midwife that I may need to use the bathroom and walk around more often, and that my appointments are needed. My lower back pain (right side, low back into upper butt) has gotten to the point though that I can't do hardly anything. I literally got stuck on the floor when I knelt to put clothes away at home and my husband had to lift me off he ground. I struggle to hold back tears everyday at work as I sit in my desk chair, attempt to get up to walk, even walking is a struggle at times. I don't even try to hold tears back at home - I just cry while my husband tries to help me as much as he can. I'm unable to twist, bend, sit comfortably, stand comfortably.. Every movement I do has me in tears daily. My midwife gave me stretches to do and said that's about all that can be done unfortunately. I feel like my boss will think I'm being a wuss, when in reality this truly is debilitating pain. The big question is: given that my boss has been less than understanding during this time, what accommodations can I even ask for? I have no idea where to start the discussion.