I am a healthy person. I have been working out twice a week since September with no problems and have lost 30 pounds in the last year eating healthy on weight watchers. Last week I took my usual Barre class, after class, we lay on the floor and rest for 5 minutes . While I was laying I felt lightheaded and my head got warm like I was going to pass out, it only got better when I sat up and took some deep breaths. I though maybe I hadn't eaten enough that day or was dehydrated, so I finished my water and drank another bottle when I got home. This has now happened to my two more times after working out and I now have a near constant feeling of lightheadedness and mild headache. Is this something I should be worried about?