bigfoot, I am surprised that your GP gave you antibiotics with a viral infection. Generally, viral infections just clear up of their own accord, and it's only with bacteriological infections that they dish out the a-biotics. Why don't you stop taking the tablets and if your lightheadedness stops, you know that it was they wot was causing the problems - and see your GP about this. Also depends on how long you havebeen taking them. He has possibly given you a limited course of the tablets, e.g. 3 a day for a week. However, hope you feel better soon. Chox.