Hi, Welcome to HealthcareMagic forum. It has been quite some time since you ve posted this query, as I do not see any answers here let me try and answer it (if that helps). Yes, you can be at risk of upper GI bleed due to prolonged and chronic use of ibuprofen and other pain killers. As NSAID group of drug like Ibuprofen cause damages to the protective layer of the stomach which increases chances of ulcerations. An upper GI endoscopy can confirm such ulceration. Sinusitis wouldn t cause gastric ulceration or GI bleed unless you also have an associated viral infection with low platelets. Platelet counts (which are part of routine hemogram) would be the indicator to confirm this. As the colour and consistency of stool depend on the type of food products consumed, if both these causes are not confirmed, the perhaps the stools changes could be related to the food consumed. Since it’s been a while now, I hope you were investigated and the cause is found/treated. However if the symptoms are still persisting, I would encourage you to consult a gastroenterologist for further evaluation. He/she can carefully examine your abdomen and subject you to the aforementioned test to confirm the pathology. Lastly, you haven t mentioned anything about alcohol consumption. If you have missed this history, it is time that you quit alcohol and lead a healthy lifestyle to avoid future GI bleeds. Hope this answers your query. Best Regards