What Dosage Of Antibiotics Be Taken For Strep Throat?

I am missing a pill from a Z-pack that I ended up not completing several months back because my doctor switched my antibiotic. It has not expired but with the missing pill I'm afraid it may not clear the strep throat I caught going around at the daycare where I work. I have all the classic strep throat symtoms. I just started this job at a local university and Im expected to return to work tomorrow because we are short on staff otherwise I would go to my doctor. Do you think 4 pills will be enough to clear the infection? How should I take the 4 pills I have now?