I get nauseous around O, usually the day of. I read that some woman are more sensitive to the change in hormones and that can cause nausea, dizziness, headaches and such. The progesterone in your body will be rising and staying elevated until AF, so maybe your P this month was a little higher and that is making the dizziness stay around?? Or maybe you had an ear infection that happened at O just by chance. I'd keep an eye on it to see if it lasts and also if it always comes back at O.