P out when I vomit? Curious if anyone has had same experience or knows what causes this?

This had happened to me before, I was drinking alcohol on an empty stomach and went to sleep, the next morning I was nauseous and everytime I vomited I would p out, I thought I had alcohol poisoning and didn't think anything of it, that was over a year ago. Well it happened again a few days ago, except this time no alcohol was involved I woke up about 4:30am and was really nauseous when I threw up it was just stomach bile and then I ped out, this happened 2 or 3 more times, the night before I felt extremly thirsty and weak, I drank alot of water and just watched tv until I went to bed, I didn't eat anything out of the ordinary, I did have to double up on my birth control pill cause I had forgotten to take it the day before, any info on what may be going on would be greatly appreciated. I know need to see a doctor but I like going in with some suggestion, so I don't get the "I can't help you unless I see you while your having symptoms"