Problems at work

Jennifer
I am 35w1d and work in an elementary school as an academic interventionist for reading in grades K-4. We are always pulled to sub for teachers or paras when they can't get a sub. Ever since announcing my pregnancy, I am always the first one to be called to sub. Not only that, but they consistently put me with violent children...kids who throw desks, hit teachers, and always have the behavior team called on them, etc at least twice a week, even when there are plenty of people around to put with them instead. Today, again, I have been told by the vice principal to sub for a para who works with a child 1 on 1 who is extremely violent. His first para had to go on leave after he broke her hip when he shoved her down stairs...to give you an idea of what he is like. I am the only person who was pulled to sub today and 2 others have offered to work with him instead...the VP said no. The secretary tried to get an actual sub through our sub service, the VP canceled the request. He said I am the only one who is to be with him today. And this is not the first time, I am put with this child every time his para is out as well as others who are also violent. I can't quit my job or leave before I have the baby without a Dr note. I don't feel safe or supported by my supervisors and don't know what to do!