What Causes Hot Flashes, Loss Of Conciseness While On Birth Control Pill?

Hi there. I m a 27 year old mother of two, I m 5 4 , 180 lbs, and I have been experiencing hot flashes. They started about 3 years ago and have gotten worse over the years. When I m on birth control ( evra patch) the hot-flashes happen about 3-5 times a week. When I m off the patch for 7 days the hot-flashes happen about 3-5 times a day. I have also been experiencing some dizzy spells and sudden near losses of conciseness. These happen rarely but usually happen when I m sitting down. Any ideas as to what s going on with me?