HI- I was also checking in on the die effects of this drug and ran into this site. I am on my 6th day of bactrim and feel like my legs are going to explode. Yesterday I had chest pain and an upset stomach. I was prescribed the bactrim on my second visit to the ER caused by a bladder cystitis. I had a very large amount of blood in my urine and bled for 4 days. I feel better but I don't feel 100% myself still. Freaking out that it has such a reaction time after the medication has finished.