Fainting in early pregnancy

I read online that while this is rare, it can happen. I fainted in front of everyone at my work today while the company was out for lunch. I had very bad cramps and sudden felt very hot and things went black. No one knows I'm pregnant as I'm only 5w1d. I called my doctor and left a message with the receptionist. I also emailed him. Is this something that I need to take care of immediately or am I ok waiting for his response?