Hi! I was put on Cefuroxime, 500 mg, for a severe sinus infection (also have had influenza past week). Now I feel very light headed, a bit shaky and weird. Almost like I am on an antihistamine. I don t tolerated antihistamines at all, but have never had any reaction to an antibiotic, nor am I allergic. Do you think it s the meds making me feel this way?