I was prescribed Doxycycline by the Student Health Center at my college for alleged Bronchitis. I've been taking 100mg twice daily, and I definitely noticed the intense nausea immediately. I've always had a strong stomach, so I was a bit surprised by how I reacted to it. Luckily no vomiting. But within 2 days, I noticed that my vaginal area was incredibly irritated, itchy, and red. I thought it was just random irritation, but it has persisted for three days, and I finally realized it wasn't a temporary thing. I've never had a yeast infection before, so I spent an afternoon researching them, and was terrified that it was a symptom of an STD (even though I'm well educated on the subject).
In my research, I somehow stumbled upon the name of this drug, and immediately searched for further side effects (since my doctor only told me to take water and food with it, avoid sunlight, and not to lie down within 1/2 an hour of taking it). What do you know, but yay yeast infections.
Basically, I'm furious with my practitioner for not warning me about all of the things I've read on this site. I've stopped taking the medicine and have no problem with dealing with a cough if it means the yeast infection goes away. I'm never taking this drug again.