I have recently been treated for a sinus infection with Zithromax (2 weeks ago). Since then I continue to have this fluid noise in my maxillary sinus when I shake my head. It is so loud that others can hear it too. It sounds like water sloshing around in my head. I have been taking antihistamines and pseudophedrine type drugs without resolve. Can you reccommend any other actions or medications? I have no fever or nasal drainiage. But, I do get a headache when I shake my head.