I don't think dreaming about using the bathroom causes someone to wet the bed, your body can pick up signals while you sleep, like a full bladder, and cause you to dream about peeing. The dream is not what caused you to wet, the full bladder or wetting is what caused you to dream about it, either before or while you were doing it. About wearing diapers - if this is something that doesn't happen very often it may be easier to deal with wet sheets than diapers, but if it happens frequently or if wet sheets bother you then you might want to try diapers. That's something you (and your parents) need to decide what works best for you.