I am a regular bedwetter and have similar dreams on occasion. That subject comes up every now and then on sites like this and from discussions I have read, I would guess that most bedwetters sometimes have dreams that they are peeing and wake up and find that they did. I don't think the dream caused you to wet the bed, I believe it's just the opposite. Your body picks up signals even while you are asleep and that can influence what you dream about. The feeling of a full bladder or even the sensation that you are peeing can cause you to dream that you are. If this is the only time it happened it could be caused by any number of things like too much to drink, bladder irritants, having a cold or fever, or just being very tired and unable to wake up. If it becones a problem get checked by a doctor. I wouldn't rush out and buy diapers because of one incident. Wait and see if it happens again and then decide.