Had flu/chesty cough which led to a chest infection for the Christmas holidays. Put on the good old amoxicillin antibiotic, which didn't really kick-in until the last day. Thought I was getting back to normal, although my sinuses were also playing up but this is not unusual for me. However, I had an asthma review appointment a few days ago and my asthma nurse wasn't happy with my peak flow reading of 340 (predicted 450) so she has put me on another antibiotic called Doxycycline to try and clear my sinuses and hoepfully help my chest. Since starting the antibiotic I actually feel more lousy with a thumping headache and no appetite. Chesty cough has gone, no wheeze but my chest feels tighter. I have been taking it with food and a glass of water as advised. Anyone ever been on Doxycyline and had similar feeling?