I'm with Fitz.
I can only speak on community level stage management.
Regardless if scheduling is well planned and detailed ahead of time or can change the night before, what I am getting from these posts is that there needs to be communication and a clear sense of organization. If you feel you are communicating well, and that is not so, sit down with your director and address that. I am also a stage manager who sends very thorough and detailed emails and schedules and information.
Be detailed and as thorough and clear as you can be and put it in writing. When the actors are there in rehearsal, be sure not to waste their time.
I've worked with directors who have called people and intended to work their scenes but changed their minds halfway through the rehearsal. VERY frustrating!
I guess some of this is redundant information, but I can't stress enough or agree enough to put things in writing, be detailed, and when there is confusion with what you understood versus what the director understood...refer to the schedule in writing. You know?
It seems, also, that you get flustered and frustrated by mistakes. We all make mistakes. Part of your insecurity may show through, which can have an impact on how directors treat you. You seem very dedicated and sweet and willing to learn. Look for ways to improve, but to do so, analyze what is NOT working. If it's a consistent problem, discuss this with the directors on ways you can improve upon those.
Okay. I hope this isn't too confusing....