Suggest Treatment For Strep Throat

I was recently given sulfamethoxazole-tmp ds tablets because I thought I may have an urinary infection and I was getting ready to go out of the country and we couldn t wait for the test results. I ended up not taking the meds because my doctor said I didn t have an infection and the symptoms went away on their on. I just returned back home recently and met with a friend who told me everyone in her family had been sick with strep throat. Today I have had a super sore throat (I used to have strep throat a lot as a child) and it feels like that...I was so disappointed since I haven t been sick with anything like this in over 3 years. Anyway, it s the weekend and I can t get in to see a doctor without paying big bucks. Do you think it would be okay to take these meds I have on hand to see if they will take care of it? Normally I would never do something like this--I always check with my doctor first, etc. But I care for my elderly parents full time (my time away was my vacation) and I don t want them to get sick so want to treat this as soon as possible without waiting until Monday to see the doctor (plus my throat is really sore!). I know it s probably not the right drug and I m self-diagnosing, again something I shouldn t do and don t normally do, but just trying to take care of things.