Plan your presentations with a montly view in mind. The simple truth is if you agree to do a presentation on a Saturday and you also have a presentation on a Monday you will need to plan time to prepare the presentation. That should be scheduled also.
In addition everyday planned activities will take a toll on your mental and physical energy. Thus, seeing the party planned for your child on your calender as well as your presentations will give you a better perspective.
This will not only reduce your stress but enable you to deliver more dynamic and energy packed presentations.