LFH
Bad luck old bean, but I wouldn't worry too much about it. Not sure how old you are, but if you are 18/19/20, you still have time to go away and remedy the situation before going back
On the plus side, you can get one of several letters; despite your letter being a 'no', at least it doesn't sound like the never darken our doorstep again you oxygen thief version that exists.
If you are of uni age, consider going and getting a degree under your belt - works wonders for the whole life experience/confidence/self reliance thing. It could be very useful a few years down the road - assuming you get in, there are still no guarantees you will make it to the front line, what with choppings, re-streams and general cock-ups from those wearing the scrammbled egg to contend with; a degree will at least give you something to fall back on now that the RAF is a less certain organisation than it once was. If past uni, Bluntend speaks sound words and that is something I would consider if you can wangle it.
If it helps any, second time round was a doddle, so chin up and crack on. It's easy for those who breezed through every stage of selection & trg to spout advice, but when the brown stuff hits the fan is when you see how people really react. As someone who has at times been knee deep in the brown and smelly, I'm a firm believer that a bit of bother en route to the final destination and how you dealt with it is not necessarily a bad thing for the whole officer qualities thing.