Sometimes the threat (and I hate to use that word) of a program's cancellation will get you some help. You can't do everything yourself! Have your brought this to the attention of your principle? Good luck!
I know how you feel! I have been doing the same thing with a few regulars covering everything that gets dropped! But I learned my lesson this year and when a few things got dropped in my lap I sent notice home and that was that. We had no after school programs, Bingo night only got picked up when they relized that no one was going to run it and it was likely to be cancelled!! You cannot just threaten though you have to follow through even if it means not doing something people are to used to you picking up the slack and they need to know you are not going to do it!! Stand firm! Good Luck!
I am in my third year as Vice Pres of our PTO. I am at the school at least once a week for SOMETHING. Today, I worked until 3 PM, ran home to get my kids off the buss and haul them BACK to school to do Market Day. While there, the lady that Chairs the event tells me she doesn't think she can do it next year and when I get home I have a message on my machine that the lady who took over the Campbell's labels and Box Tops for Education is leaving all her "stuff" in the office and that I'll have to find someone else to chair it. I literally started to cry! There are two of us board members who do just about everything, with the help of a handful of mom's that, bless their heart, keep coming back. I am at my witts end! I don't think I can take on one more thing without a mental breakdown. What advice can I get to "ask" for help from parents and let them know that if they don't "step up", then there will be NO MORE!