I experienced dizziness, followed by tunnel vision, loss of hearing, cold sweat, then passed out. I came back to conciousness quickly, this happened to me about a year ago but I didn't go in to see a doctor then. I'm pregnant now so I'm a bit concerned because I know passing out is from loss of blood flow, and I know pregnant women are supposed to have increased blood flow. Any ideas? I wasn't hungry, or dehydrated.