Kitty, you run that place! Youre a jill of all trades! You know they couldnt keep that place going without you. You can replace almost anyone who is out sick! I would tell them, the one thing i would have done differently, is ask for more money and a better parking spot.
One place i worked, when i left, they had me hand off my work to FIVE people. All the other contractors who left, handed over their work to ONE person. The way you talk about your job, you know they would be in the same spot if you left. They DEPEND on us mad scientist types. And they know it. Let them know you know it too.