Could I have Irritable Bowel Syndrome?

For the past few months I have had diarrhea (sometimes very painful) after I eat. I avoid eating until I am home from school because the first meal I eat is always the worse and I often go to the bathroom two or three times. I sometimes will take anti-diarrhea pill but that is usually after I have had a few bouts. I almost never experience any discomfort or diarrhea after that first meal and my bowel movements are usually fine the rest of the day. I don't notice that it is made worse by certain foods, I have eaten everything from hummus to ice cream and it is all the same. I used to get really bad diarrhea when I had milk but i've noticed that I no longer do. Do you think this could be irritable bowel syndrome?