Hello I appreciate your concern Looking at your history this could be related to chronic constipation or colitis which means inflammation of the intestine Bloating can be caused by Aerophagia (swallowing of air) can be caused by smoking, use of alcohol or carbonated drinks or an ill fitted denture. Another reason for bloating can be acid peptic disease like gastritis or peptic ulcer. IBS is generally gets precipitated due to stress and anxiety and altered feeding habits So I would advise you to consult a gastroenterologist for physical examination and a battery of tests including an Endoscopy if need be to confirm the diagnosis. PCOD is a different issue it also can contribute to these symptoms as it affects hormones irregular periods are very common with PCOD so need not to worry You can recheck for pregnancy test, I am sure it will be negative if you didn t have unprotected sex. Hope this answers your question thanks and regards