Achillis symptoms and conditions

I personally have taken avelox for a sinus infection and experienced severe dizziness and disorientation as well as a very metallic taste and extreme fatigue. My sister was recently given the medication for a kidney infection. She took 5 days worth of a 10 day script. She developed tendinitis in her achillis and has been in constant pain throughout her entire body for over a week now since she discontinued the medication. Each day I keep expecting her to be at least a bit better (she's basically bed ridden from the pain) and yet each day she is not. Can anyone PLEASE tell me, if you have had a similar experience, how long did it take you to recuperate? I would like to be able to give her some hope but also I'd like to get an idea of what we are or might possibly be dealing with.