Hi ! As your appendix is already removed, this angle can be safely excluded now. With all probabilities, presently you have got infection of your intestines due to eating food from outside. Get your stool tested both routine for ova/cyst and also culture and sensitivity test. In the mean while you should consult your family doctor to start you on some empirical antibiotic for intestinal infections and change if required depending on the culture and sensitivity report. He may also add an antispasmodic and a proton pump inhibitor along with a probiotic for you.On the dietary front you should go for fresh curd, banana and bland diet with plenty of liquids with electrolyte content to keep you properly hydrated. On a long term basis and because of your IBS history, you should avoid eating regularly from outside. So far as practicable, I will advise you to cook you own food at home and eat more of roughage and liquids. I am not aware of your job profile. Try not to stress yourself too much as stress is known to precipitate symptoms of IBS once you are already diagnosed with it. I hope this helps you for the present. Good luck.