My DD found the AS Geography very difficult too. She has worked soooo hard for it and in the last few weeks has really made progress.
One of her teachers has been giving her 1-1 intensive help in free periods and at lunch times. DD went into the exam feeling really confident that she knew the content well but now feels as though she has really let her teacher down. 
Poor girl has only recently diagnosed with a visual processing problem (Meares Irlens) and has really struggled with some of the AS level content.
She processes what she reads at a snails pace (the Ed Psych who diagnosed her was baffled as to why it hadn't been picked up before)
The school have put some extra help in place for her but it was only in the last four weeks or so. Thankfully she has 25% extra time and has her exams printed on coloured paper and can use a laptop to do her answers but nothing would have been enough for this exam- she found it impossible.
I feel so sorry for her.
Hopefully her other three subjects go well so this one won't matter.