Doxycycline Hyclate Side Effects: Been on a 7 day 100mg course for sinus infection. Ive felt dizzin http://www.medications.com/effect/view/33865 Been on a 7 day 100mg course for sinus infection. Ive felt dizziness, headaches, nausea, tingling in my arms and legs, heartburn, stomach cramps and my throat and glands swollen up. Also Ive been left with no energy and sleeping for 12 hours a night. As soo What are you doing for your sinus infection now Tue, 02 Sep 2008 20:16:43 -0400 http://www.medications.com/effect/view/33865?item=11891 What are you doing for your sinus infection now http://www.medications.com/effect/view/33865?item=11891