Oh, you weren't told--you are supposed to show up, go to your first stop, and then call claiming the injury occurred while you were delivering your first stop. That way it is a comp injury and you are all set.
Yes, I am just kidding, although we all know of some of our co-workers who have tried to pull this stunt (with mixed results).
I hope that you have supplemental health insurance and/or disability insurance.
Take care of yourself first and come back only when you are ready.