Re: given bactrim for strep?
Lots of antibiotics will treat strep - it's just that some are more (or less) effective than others. And penicillin-based drugs are preferential for strep cases. My mom is allergic to penicillin among other drugs and they always have difficultly finding something she can take.
In any case, I can't remember for sure, but I want to say I have taken Bactrim for strep. I took lots of different antibiotics because I got such frequent infections that they would try different medications in hopes that one of them would knock it out better. I would just take it and if you aren't feeling significantly better in a few days, then it would be time to call the doctor and let them know how it's working so they can try something else. But I imagine they gave you what they thought would be most effective considering your allergies. Hope you feel better soon!