I know how you feel By Mi Vida Loca

I have had teachers request me for maternity leave, and then the office place someone else there, I have been offered perm. positions, for different classes, and turn down other schools for a month or so, and then all of a sudden they want to combine that class with 4 other teachers!

Where I work, if you turn down a certain school, they turn their nose up at you. They all have their picks, and it is tough to get a full week sometimes.
I would talk to who ever calls the subs in, and explain to her that you have turned down other jobs, and is there any way that you could come in to fill in somewhere else. Tell her that you need and WANT the work. Maybe she'll understand.

Hang in there, times will be tough, but you'll get through it. Stay strong.