I have had chronic diarrhea x 7 months. ALL tests, scans, labs, stool 72 hr, lactose, you name it, I had it and ALL tests came back negative. BMs at least 10 x day. I do have post nasal drip. Could this cause diarrhea to be consistent for 7 months or more? How should I treat this to get rid of diarrhea? Thank you.