sorry to hear about that.
have a look at your documents against their decision and as the Boss said, correct it. if you dont think theres nothing wrong with it, strengthen it instead.
i think the fact that you are not working makes them doubtful that you will not come back when your visa is due to expire and when your pocket money is spent that you will seek employment here.
try again and look at it this way - the weather here is not very inviting anyway, youre probably better off coming over when its a bit warmer.