Suggest Treatment For Stomach Pain And Irritable Bowel Syndrome

I have been having stomach pains and irritable bowel syndrome. I have had this before but never more than a week. Dizzy. Nausea. Weak. Feel like crying. Pain up to my chest. Is this just anxiety from depression and alot of family problems and other problems. Or is this more? I don't want to go to the doctor to be given more prevacid. I am taking depression meds. Am I just stressed to the max? Stomach is the first place of my stress. Headaches with it and back pain on and off. I'm afraid to eat now. And I am obese. 260 plus. I am 5'4". Thanks.