Diarrhea, Gas, Roaring Noise, Intestinal Pain. Taken Mebeverine. Help

Hi, my name is Emily and I am a 15 year old girl attending high school and i have a major problem with my bowels. The symptoms i am suffering from include diarrhea, constant need to go to the toilet even after i have passed stool(I have to go to the toilet around 6 times in the morning), a gas like movement in my intestinal area, roaring noises coming from my stomach/intestines, constant need to pass gas and sometimes severe stabbing pains in my intestinal area. I previously went to the doctors and got diagnosed with IBS. The tablets i was given was mebeverine and i have to take them 3 times a day. These symptoms cause me to get nervous in class and makes it extremely hard to concentrate on my work. Whenever the class is quiet my bowels make noises as if passing gas - even though the gas hasn't left my body. It is causing me to have very low esteem and i would be extremely grateful if i could get help. These tablets have had little if no effect on me. Thank you for reading this.