At the end of Aug. I was diagnosed with an upper respiratory infection, in time it went away. About a week later I found out I had mono and spent two weeks resting, and not being able to exercise at all. Yesterday was the official end of my mono, and I was glad because I should be feeling better, but I had been coughing a ridiculous amount, so once again I visited my doctor. I was told I managed to get an upper respiratory infection again and she decided to put me in BIAXIN XL 500 mg. Last night I had nightmares and woke-up an hour after falling asleep feeling fully rested, but paranoid about it being dark in my room [since I was little I have not been able to sleep with light, I sleep best in complete darkness], after this weird experience I managed to fall back asleep. I woke-up in the morning feeling very depressed, but figured it would go away and was just due to a nightmare I had. So I got ready for school, and the day just got worse, I was extremely irritable. Nothing went wrong, I was even giving some surprisingly good news, but was still very depressed. I got home and just literally had a nervous break down. I cried for about an hour straight and just could not stand anything in my life. It was the worst I have ever felt. I finally got it together, and decided to come online and check personal experiences because my doctor had told me it was impossible one dose could do this to me. But, others have gone through what I have just experienced and I have realized it must have been the medicine, because I am generally and very cheerful purpose. Needless to say I will not be finishing my prescribed dosages.