Suggest Remedy For Cramps And Acid Reflux While On Trimethoprim

Hello I currently have a kidney infection and I am taking trimethoprim for it. It is making me soo ill I have cramps , I feel sick ,my back pain hasn t gone my symptoms have not gone . I have acid reflux and ibs. I am unsure that if I should go back to my GP to find out what s the matter or if I should take buscopan to get rid of the cramps . Thank you x