I fully agree with the above comments, join some clubs, get stuck into your degree, etc.
I too applied, keen as mustard but pretty niave, to join the UAS during my first year at Uni unsucsessfully. I cannot say I had the best interview bit nevertheless, it was dissapointing not to be accepted. When it came to applying to join the RAF, having not been in the UAS and indeed making that clear at the AFCO, in no way put me at a disadvantage, and I sucsessfully got though OASC.
The UAS, just like the ATC, is very much a recruiting tool for the Air Force, that is its purpose. Without being too censorious, the UAS is pretty much like any other University Club or Society - a drinking club, although slightly more formal, I'll admit.
Anyway in an end to this ramble, The important thing - Do you want a career in the RAF? It appears that you do. It so, a setback like this is more likely to be benifical to you when you go to Cranwell for four-days-of-fun at the end of your degree.
Good luck, and enjoy University!