Requirements outside my job description?

I've posted here before regarding a student I have that is completely out of control, violent and cussing and has now started threatening to kill people. He's 6 and I have to restrain him on an almost daily basis because of how viciously he attacks me and others.

He had an aide go to gym with him every day, because he can't be left alone. Well the aide is now gone and the principal told me that I am now required to give up my 35 minute prep to stay in gym with this kid. I'll now have a 20 minute prep at the end of the day, which doesn't work due to needing to help my co-teacher gets the kids packed up to go home. Plus I have bus duty.

I am also a special ed teacher. Last year I was told it was illegal to give intervention services to non special ed students. Now I was told I have to take a general ed student from another classroom with me to my intervention time with all my special ed kids. This student does not have an IEP and he requires help with something I'm not even working on with my students. Why can't his actual teacher help him?

It's only my second year and I feel like I'm getting taken advantage of. Am I being over dramatic or should I do something about this?