I Have Been Told That I Have IBS. Ive Been

I have been told that I have IBS. Ive been instructed to take different over the counter medications such as Prevacid, Simethicone, Calcium Carbonate and even charcoal pills. Sometimes in combinations of each but nothing seems to ease the gas and stomach pain I have during day but mostly in AM and PM. I am very regular with a bowel movement every morning when I get up. Any suggestions as to the diagnosis or the medications to help me. Len