Why am I getting a headache during and after a workout and what could be done ab!

Why am I getting a headache during and after a workout and what could be done about it?

This has never happened before and I used to work out pretty vigorously too. Now that it's beach season and I have not been working out for months, I have began to work out 6 times a week for 50 mins each time. The first few days of the week everything was fine, but today I woke up with a huge headache. The previous day I had a very vigorous workout. Towards the evening the headache went away and I decided to exercise again, but about 10 minutes into it I began getting a headache again. I'm not sure what I'm doing wrong - what could be causing this headache and what could be done to stop it from happening?

2 weeks ago
Please don't say dehydration because I drink several bottles of water daily, several times throughout the day and not only when I'm working out. Also don't mention poor diet, because I've actually began to eat healthy a month ago and have even been staying away from all sugar and junk food and eating balanced meals, not to mention taking a daily multivitamin/multimineral and omega 3.

you should eat a healthy snack before and after you workout to keep your blood sugar up otherwise they will drop too low and you could get a headache or pass out. I recommend eating some protein before you workout like apples and peanut butter, low-fat string cheese, low-fat yogurt, or a hard boiled egg. After you workout your metabolism is at its highest so eat some carbohydrate-rich foods like whole grain crackers like triscuits with cheese, pretzel sticks, whole grain cereal, or a granola bar.Also don't forget to hydrate! If you are exercising vigorously for more than an hour drink at least 8 ounces of water every hour otherwise you could become dehydrated!