Should you continue to apply, you will eventually get in. Of that there is no doubt.
However, the manner in which the RAF is handling your situation beggars belief. A misdiagnosis by a RAF employed doctor, followed by a "Close, but no cigar," letter is typical of the man (mis)management we suffer today. I mention this because you need to be aware that, whilst the flying and operational stuff in the RAF is 2nd to none, the admin and personnel policies are 2nd to all.....