Is a dream anything else but a dream?

Sometimes you have silly or meaningless dreams but do you ever have dreams that when you wake up you think, hang on a minute, was it or wasnt it. I can remember some of my dreams from 6 -9 months ago and seem so real. belive it or not some of them actualy come true but only in the day to day things, nothing big like winning the lotto etc etc. Sometimes when I realise that Ive just gone through the motion of a certain dream its like its unblocked a dajavou dreamy moment in which I know Ive already lived. anybody else had the same???