Don't quit on it now, person!
Think of it this way: the amoxicillin is a flock of hillbillies trying to shoot some pesky raccoons (the infectious bacteria) that keep digging through their trash barrels and climbing into their attics. The fat and slow raccoons are the ones that get shot first, and clearing those chumps out will make it seem like there's less annoyance in the hillbilly community. There's a problem though: if the hillbilly mob stops now, the faster, stronger /more annoying/ raccoons that escaped that initial onslaught will just come back, breed with one another, and the whole hillbilly community will be even worse off than it was before they started their 'coon hunt! Instead, you need to keep chasing down those peskier, stronger raccoons until you've eradicated all of them so you don't just let the really troublesome raccoons come back and start really causing a ruckus.
Boom roasted.