:wasalamex
First of all you should relax insha'Allaah because you have to realise that its part of your destiny, which is one of the important beliefs of our faith.
Like you might be scared right now that you never got to go, but something could have happened in the exam which might have lead to it being a F.. But we know that never happened because it wasn't written in your destiny, the same way - you weren't able to do the exam on its proper date- which was written in your destiny.
The second thing is, that if you were really ill & if you still are, you could go to the doctors now and tell them how long you've had the illness for - insha'Allaah they could create you a doctors note proving that you were really ill insha'Allaah?
You could also pay another college, or maybe even this college to re-book the exam? I don't know how this works, but i think you can pay for the exam paper and its booking etc. insha'Allaah.
You could even phone up your local doctor [your GP] and phone him/her up to ask for a doctors note and explain the situation - they may help insha'Allaah. But even this may be charged for, Allaahu ta'aala a'lam (Allaah Almighty knows best.)
Also, make lots of dua' (prayer) to Allaah Almighty, so you can take the exam, and so you pass with an A insha'Allaah. Also pray to Allaah to help the muslim ummah (nation) and that we all be succesful in the real test, and that is the test of the hereafter.
:salamext: