Nancy -
Keep in mind the energy required just to get yourself ready to go to work. The shower, dressing, drive in, etc. That can sap your energy. And your kids understand. I know my teenagers are much wiser with all this than I am at times. They keep telling me to take it easy, take my time healing, not to feel guilty, etc.
If you go back too early, you will do yourself and your students an injustice. If you don't have the energy to do all the walking and such, you won't be doing your best work in class. Be patient. I have to remind myself that my kids (and your students) look to me as a role model and by demonstrating how to take good care of myself, they learn it is okay to take time for themselves, too. I can relate to your guilt, but I'm learning that it is important to take care of myself first so that I can better take care of others.
I will keep you in my prayers that you make wise choices and allow yourself to heal.
God bless,
Skeet