I'm sorry for your situation but I don't think your flying school should have let you get to that stage.
In the UK, many schools will mandate that Air Law has to be passed before they allow first solo (although that's not a legal requirement). Most schools will also require that all exams have been passed before you do your final skills test so I am surprised that your school let you take the skills test with having passed so few exams.
If nothing else, I suggest you have a word with the Chief Instructor as I would think that some responsibility lies with them to hopefully give you some extra tuition (free!) to help you through this last exam.
Air Law is tough because it's boring. You just have to learn by rote. However, having some flying experience now, you should find it easier. I passed Air Law with the grand total of half an hour in my log book!
Cheers
Whirls