antibiotic just for a couple of days? Doesn't sound right to me.

It is commonly agreed (From my pd, any respectful newspaper or magizine) that you have to take full length of the antibiotic (usually five or ten days depends on the medicine) regardless if you'r well or not. And it is better not to skip any dosage. If you don't do that, you risk greater chance of getting infected by superbug without easier treatment.