It is obvious that you have prolonged diarrhea. Chronic diarrhea can be due to several reasons including those you mentioned but need several medical investigations to reveal the exact cause.
Irritable bowel syndrome (IBS) is functional disorder and can be confirmed when all possible organic reasons will be excluded. Possible organic reasons for chronic diarrhea are: infections (bacterial or parasitic), inflammatory disorders (ulcerative colitis and Crohn's disease), systemic disorders (diabetes, hyperthyroidism), colon cancer, malabsorptive disorders (celiac disease, lactose intolerance, food allergies...), certain medicines etc.
Have you ever done colonoscopy?
Have you ever been tested for intestinal infection - coproculture?