I was recently diagnosed with a bladder infection and put on Bactrim. I have been on the antibiotic 3 days. I now have  constant lower back pain on both sides, nauseated after eating,headache, chills and shaky. My weight has been fluctuating for quite some time often gaining six , seven pounds in a day. I have common variable immune deficiency. Could this have progresssed to more than a bladder infection?  , and what is the best course of action .
HI thank for asking to ChatDoctorI really appreciate your concern the anti-biotic (Bactrim) is the best medicine and no need to change this you have to complete the course of this medicine till 7 days, Chat Doctor.