Been on antibiotics for 3 1/2 days for strep. threw away tooth brush, but still no better throat still hurts, still headache, low grade temp. should i give it more time or go back to doctor?

finish course of abx and continue with supportive care methods

It is never inappropriate to contact any of your treating doctors for advice, clarification, concerns. That's part of "treatment." By 3 1/2 days your symptoms should be easing off a bit. Keep taking your antibiotics for the entire cause of treatment, but let your physician know of your questions.