how can i help my cat?

She's been having watery diarrhea for 3 weeks now, i've already taken her to the vet but they said it's not that serious coz she's still responsive, she eats her food and drinks her water, she still plays from time to time, and she never vommited once. they gave her teitozine and metronidazole for her meds but it's been more than a week and it's not doing anything. what should i do?