Hi,
I understand that it is very disappointing, but you should keep your spirits up and try to analyze what exactly went wrong.
look into the factors that could have probably affected you performance in the actual test. Summarize it and work on it.
If you ask me, I would advice you against taking the test in 16 days.
Since you are already in pressure you may go wrong again. Take some time off, calm your nerves and then hit back after 40-45 days when you feel confident enough.
It will give you sufficient time to revise everything once again and work on your strategy.
All the best.