Suggest Treatment For Sinus Infection With Headache And Nausea

hi i have a sinus infection at the moment and am taking an antibiotic called klacid i've been on it for 5 days now. yesterday and today i hav a blinding headache in the centre of my forehead along with nausea. i really dont think its a a sinus headache i think it might be a migraine or a rection to the antibiotic. what do you think?