How Can Constipation And Abdominal Cramps Be Treated?

Hello, I m 73, am on chemotherapy as neoadjuvant treatment for Stage III breast cancer. Became constipated after chemo #2 (14 more to go!) and have bleeding hemorrhoids. Because white blood cell count low, vulnerable to infection, so am on Amoxicillin/Clav. Took much in the way of stool softeners and laxatives to free up feces, then got diarrhea. Pain on passing any type of stool--hard or soft--is excruciating. Now that diarrhea has passed, am so constipated that I m having deep, pulsating gas pains so painful I m screaming into a pillow! If blood values are up, should have 3rd chemo treatment on Monday, but miserable between now and then. PLEASE HELP. With Gratitude, J..