I am an experienced runner, I have been running long distance for about 8 years now and I am very familiar with the amount of water to drink and what kinds of foods to eat, how long before a workout, etc. Lately every time I finish running I feel very dizzy, weak, and nauseous, almost like I am going to faint or vomit. It usually lasts an hour or two, and it sometimes helps if i eat or drink something very sugary right after running. I have never had problems with this before, and I am wondering if this is normal or is this something I should ask a doctor about? Any suggestions?