Bactrim and muscle spasms

I was prescribed Bactrim for a staph infection that turned out to be MRSA. I took the pills (2 pill 2x a day for 10 days). It did clear up the infection; but the side effects sent me back to the doctor. After the second dose, I started having a headache and feeling feverish. After the third dose, my muscles started aching and I began having little muscle spasms and numbness in my right arm and a low grade fever, headache and fatigue. The morning after the 5th dose, I woke up with severe muscles cramps in my legs and feet. I took the 6th dose and what a mistake. The muscle cramps and spasms moved to my inner thigh, legs, feet, abdomen and back. I had to use heat packs to quiet the muscles. I stopped taking the meds and notified the doctor. He changed my prescription to doxy and said that I was allergic to sulfer meds. He also gave me flexorial to help with the muscle spasms. It been 3 days since I stopped taking the meds. I still feel severe fatigue, muscle aches, fever, sweating, and anxiety. I will never take this stuff or anything like it again. I have noted it in my pharmacy charts so they will no ahead in case I don't catch it.