Suggest Treatment For Sinus Infection After Taking Musinex

I have been taking maximum ssrength musinex D (1200 mg guaifenisen , 120 mg psydophedrine) extended relief bi-layer tablets). It says only take every 12 hours, but I keep forgwtting when I last took one and am sure I have taken more than directed. I have a horrible sinus infection, so I just wanted it to help loosen the mucus. Can I OD from this? I also took one vicodin for pain...