Fluoroquinolones interfere with thyroid hormones. IMany of us (from another site) have found that we have Hashimoto's, which is that our autoimmune systems are attacking our thyroids. Also, there's a possibility that your adrenals are shot too. Now that I am on Armour (pig thyroid) all of the horrible tendon issues, anxiety, fibromyalgia and chronic-fatigue-like symptoms have abated. I am walking long distances again. Suggest that you all have these tests done: FREE T3, FREE T4, and thyroid antibodies test in addition to the TSH test that they will always do. Also, be aware that your TSH test score should NOT be above 2.0. Your docs will erroneously insist that anything under 5.0 is ok. WRONG. My scores were in the 3's before being floxed and in the 4's after. I also take tiny amounts of Cortef for my adrenal fatigue.