Vent: at a crossroads

I work in staff development. I am so bummed out right now. I have done this for almost two years. I have been hoping for improvement, but things are only getting worse. There is a big part of me that longs to return to staff nursing. Really I do love education. My problem is that I go into work never knowing if I will be staff or educator that day. I work almost 10 hours a day, five days a week and sometimes more. My salary is set and I do not earn overtime, but can take another day off if it is not busy, which it usually is. I have one large unit I work with and two smaller ones. The nursing staff on the smaller units often float back and forth between the areas. The larger unit staffs itself. I came from the larger unit as a staff person of almost 15 years at the facility. In my job description, I do not do patient care. In reality, I do it all of the time mostly on the larger unit. Now I am being pressured to act as charge nurse on one of the smaller units, when there is a callout or shortage. As I am not intimately familiar with this unit and have a great deal of education to catch up on, I do not feel as though I should have to do this. My goodness, I already am working as staff when I do not have to and still that is not enough. I feel like a hamster on a treadmill. I like patient care and am happy to help, but I am only one person. My phone often rings on the weekend and nights with a call for help when they cannot reach one of our managers. I suppose this is burnout. The fall is coming which I dread, since I am taking two classes and have two teens at home. That just makes all of these extra hours and work even harder. I know the staff is burnt out too. By the time they call me, everyone else has said no. ARRRRRGHH! Any suggestions anyone???