When to stand up for your rights?

:angryfire I am in a tough situation. I am a unit manager at a LTC facility. We had a new DON come in about 8 months ago. To make a long story short, the other day, she was talking to the other unit manager (nothing to concern my unit) and the Administator called out and wanted me to come into her office to talk to her about something, so I got up to go into her office. When I did, the DON pointed her finger to the chair and told me to sit. I felt like I was being talked to just like a dog!!!!!! It was not just the words, it was more the tone and the "I am telling you to do it, and you will obey" tone. I am contemplating going to the administrator over this situation. She is currently treating the other unit manager like crap also. She just hangs her head when she does this. I cannot go on this way. My evaluations are nothing but wonderful. When I asked if I was doing something wrong, she just stated" No, I am the DON because I am lazy, and know how to delegate well!" I cannot continue to work under this type of stress!! Please, any suggestions?????