Tales from an Overextended Mom

I am overextended.  Not necessarily in the financial sense, although I'm far from flush with cash, but in the time sense.  As in, I have none.  Less than some.  No extra.  Zip.

I must learn to say no.  I must learn to say yes to tasks that make me money, and no to a few things that make others money.  In the last few weeks I have been running a book fair, helping wee ones pick out bling for their mom's at the holiday shop, crafting ornaments with girl scouts, and handling recycling for the elementary school.
In the next few weeks I am going to help at another book fair, suggest a coffee mug for dad at another holiday shop, help with math games, craft ornaments at another workshop, and deliver collected toys and crafts to two local organizations.

Oh yeah and I have a severely past due deadline to contend with, and a few other employment opportunities to move to the top of my priority list.

All bitching aside I do love volunteering.  I love being involved at my daughter's schools and I love helping out where I can whether it's at school, church, or elsewhere.  The problem is that these endeavors are wearing me out and when it comes time to complete tasks that pay me money I have nothing left.  These endeavors also cut into my "me" time, which for the last 10 weeks has involved time at the gym.  I'm on the fast track to 40 and I am making significant changes in my physical health before it gets here.  But if I'm worn out mentally, the feelings overpower my physical strength and not only do I not complete work I get paid for I don't do the work I want to do on me either.

I'm not sure there is a solution to my over extension.  My several jobs, two kids, two dogs, hubby and a house all add to my stress, but I have to cut back for so many reasons the most obvious of which is my sanity!  There are only so many mental health trips to Target-with-a-Starbucks that I can squeeze in to my already negative time balance.  So, what do I do?  What do you do?  I have such a hard time with repetition in my schedule that to live by the hour seems horrific.  But is it the only way?  Must I schedule "me" time so that I don't fill those hours with "them" time?

I'm clueless.  And I'm open to suggestions.  What can I do to find a healthy balance?  What is the proper work-me-them balance?   I'm too tired to think.  Share your wisdom, or your lack of.  I'm all ears.