Seems you get frequent syncopal attacks which may have a number of causes. Though a bit of elaborate history would have helped more, but for now, calm down, and start taking plenty of fluids. Add salt to your diet, in form of over salad/ fruits. Keep a target of atleast 8-10 glasses of water everyday. Also observe your urinary pattern, and how many times you urinate. Shall help to come yo a clearer picture. Avoid prolonged standing and immediate standing after lying down. All we can do is take these precautions for now.
Next Steps
follow up with BP when such episode happens in future.