I took Bactrim last year for an infected cyst and had no problem. I had another infected cyst had it lanced and was prescribed Bactrim again. The first night I took it was very sick to my stomach. The next day was tired, diahrea, frequent urination, cramps in my legs, shortness of breath. Day 3 took the pill in the morning and continued to feel like I had been hit by a truck, that evening cramps so bad in both legs I could not walk. Did not take the pill that night. If I have taken this before and no problems, why this time? Still feel like crap