I was put on bactrim for uti. I was fine until the 3rd day were ...

I was put on bactrim for uti. I was fine until the 3rd day were i began experiencing flu-like symptoms. The 4th day i got worse and that night i developed a fever of 103 i couldn't look up or side to side because of the pain. I woke up that night drenched in my sweat and when i woke up that morning i now have hive from head to toe that seem to be getting worse even with benadryl. I'm feeling extremely depressed and don't know what to do. I would never wish this on my worst enemy.