Hi ,
Loose stools of infection origin are mainly from gram negative and anerobes And ofloxacine being floroquinolone covers gm negatine n metronidazole covers anerobes . After few days of treatment bacterial load decreses but still there and patient becomes symptomaticaly better(feeling of wellness develops) hence drugs should not be stopped at this stage otherwise chances of recurrent infection , resistant strain develops .
Both the drug has very less risk benefit ratio n can be given for complition of its course . So don't worry n have faith on your doc and complete course of both drug.

Hope this ll help

Thanks n regards