http://www.medications.com/effect/view/26642 This is my second day on Doxycycline.I was prescribed Doxycycline yesterday, for a sinus infection. I am on 100mg BID. my sinus infections are, well, I get on an antibiotic about once a year. This is, I believe the first time I've been on Doxycycline. Yeste Sun, 27 Jan 2008 20:40:57 -0500 http://www.medications.com/effect/view/26642?item=4406 I've been on Doxycycline for 4 days now and it's not doing anything. In fact, I feel worse. not only am I still miserable with the sinus infection, but now everytime I take this med I fall asleep and hour later and feel shaky and nervous with it. Is this n http://www.medications.com/effect/view/26642?item=4406