bacterial infection
"I have been taking Bactrim for a total of 3 days. I have awful headaches,  the shakes, spiky fevers, tightness in my chest, and can barely keep my eyes open from exhaustion. I have 7 days left of treatment and I'm not sure I'm going to finish it. I feel worse with the medication than I did with the infection.

Granted, it has reduced swelling and pain at infection site. So I guess it's doing one thing right."