You can get your bagged spinach once again, just not from California.
The FDA is allowing spinach from areas not connected to the E. coli outbreak. Even though you were likely in good shape getting it from a farmers' market, people weren't being too sure.
The investigation is still not over, and it's taken awhile (a good thing in my mind — I want a thorough investigation). More updates to come.
If you are feeling unsure even now, buy frozen or cook the fresh stuff. Or try a temporary leafy replacement.