How Can Diarrhea Be Treated?

I am suffering from a diarrhea almost a watery stool for almost two weeks, at first week i went to a doctor for a check up and collected fecal sample from me for lab test then after reading the report he prescribed a anti diarrhea medicine and a gastroaide capsule. However after taking that medicine for almost a week nothing change to my condition, so i decided to went into another doctor and told him of my first check up and the prescribed drug. She ask me what was the finding on lab test and told him that i have +4 bacteria based on the result and the color of my poop is yellow more of liquid water, gas and bubbles and my stomach is sound like grumping. Then she prescribed the metronidazole which i take twice a day, then my poop turn green and watery poop was lessen a little bit and bubbles went out. It s my forth day now taking the medicine which is i have to still finish 6 tablets since in the prescription was #14 twice a day.if in case i finish the recommended prescribed number of days i should took the medicine and my poop was still watery, should I continue the medicine and what perhaps the condition that I have why I have severe diarrhea which I forgot to ask my doctor.