Problem

I have a problem:

I'm a para working with mild/moderate learning disabilities children in 4th and 5th grades.

Before working as a Para, I was a  Substitute Teacher, and before that I taught at the college level.

My "Supervising Teacher" calls for a sub 3-4 days per week, since she's working on her national certification. This creates incredible stress.

I've already been a Para for this teacher for only 3-4 weeks. She, the Supervising Teacher, has all kinds of grading and tracking, and developmental reports she does, and has

changed their schedule at least twice since I started. When I once asked her if I could develop my own lesson plans for when she's abset, she said that she felt uncomfortable iwith that and wanted to be able to go over and approve whatever I came up with first. This sounds perfectly reasonable to me, but she's absent 3-4 days per week and we have not yet had time to go over her lesson plans, scheduling, grading, or the nuts and bolts of how she teaches. Two of the Assistant Principals at the school told me in a meeting, that since I am the Para, I am expected to essentially take over the class when she is not present, and teach the class, and basically tell the Sub to take a supportive role for me. Every time a sub comes into the room, s/he states that the lesson plans are so complex as to make no sense at all-with the class being divided into multiple groups, and each group doing different activities on laptops, or in books, at different times. And with the kids being mild/moderate LD, they need alot of structure or they become extremely disruptive. Some children in class will cry, curl into fetal positions and sit by the door of the classroom, others will just storm out of the room when they see another sub.

In a meeting with two Assst. Principals, a few days ago, I was told that the last time a sub was there, the class became so disruptive and loud that I was expected to take charge of the classroom and teach from now on whenever a sub is called--and that quality of subs could not be pre-determined. I explained that my supervising teacher had me working with other teachers most of my day and I was not in the room during these disruptions and I did not know that I was expected to take over teaching when the regular supervising teacher is absent. 

I can study my supervising teacher's sub lesson plans for an hour or two over Spring Break, but she changes things regularly and doesn't want me to improvise when she isn't there. I feel like I was lied to when I was hired; I felt that I was being hired to assist the teacher, not essentially take over teaching for the forseeable future. What are my options?

Any advice or input? I'm thinking of asking to be placed with another teacher who may have a more stable schedule with students or just quit and go back to subbing - and then when I can finally teach full-time myself, do things my way.