No, it will not clear on its own.
Here is a link about Coccidia:
Coccidia
One about Parvo:
Parvovirus: Serious Diarrhea in Puppies & Dogs
It may not be either of these. Could be related to whatever you are feeding her...did you change her diet at all?
You need to make sure she is hydrated...and also that she does not get hypoglycemic.
Dog Hypoglycemia (Low Blood Sugar): Symptoms, Treatment, and Prevention