There is nothing to worry so much. Generally diarrhea subsides automatically after a couple of days. In such instances, you have to retain water and electrolytes by drinking plenty of water. Taking Oral re-hydration Salt or lemon juice. Preventing dehydration and providing relief from the symptoms. Although you should not neglect constant diarrhea as it is one of the common causes of preterm labor. You told that the stool cultures for parasites and bacteria, and blood test came back good, even if you have chronic and disabling diarrhea, you should consult your doctor for further investigations to find out the exact cause of these symptoms (e.g. inflammatory bowel disease or irritable bowel syndrome ). All the best. Take care.