Getting Used to Schedules

Today was a short day for me. I teach during the school year, and then I have scattered amounts of time off during the summer. Every time Lilly has a change in her schedule she reacts terribly, gets used to that schedule after about 1 or 2 weeks, and then does it all over again every time I switch back / forth in to school mode vs. vacation mode.

Today she barked if she was left outside, wouldn't stop pacing inside, and then finally stopped for a rest behind her chair...She keeps me on my toes no matter if I want to relax or not! I also have an underlying medical condition where I need rest at times. Does anyone have any ideas for me in order to better her transition each time she must get used to a new schedule? She is almost 4 years old now...So, it might be difficult.