Had Wicked Diarea Overnight A Few Hours Took Immodium This

had wicked diarea overnight a few hours took immodium this morning went to the bathroom (not as loose ) one time since but severe stomach pain bloating and shooting pains uo into left shoulder and back area i had gastric bypass RNY 4 years ago but im not dehydrated trying to do ice chips to keep hydrated most pain is center of abdomen. do release gas at times but no relief please help