I am having itching and red rash/splotches on my chest, neck, arms and legs. I also was very nauseous and throwing up. I took Bactrim for redness all over my right lower leg after total knee replacement. other drugs I take are irbesartan, bystolic, terasozin, glipizide, crestor, prescription fish oil, lantus and victoza. what could I be allergic to ??