Hey there,
I just wanted to share my story with you. I was given a 1/123 risk of downs and proceeded to have an amnio, which was scheduled for four weeks after my 12week scan. It was honestly one of the hardest times of my life, but now with the benefit of hindsight it was well worthwhile. Thankfully we received the all clear today and we can finally enjoy the pregnancy. The procedure itself wasn't painful, slightly alarming but certainly nothing unbearable at all. If you are offered the FISH test I would recommend it, results in around 24 hours. Although you can't claim on Medicare, the fast result meant we could move on (one way or another) quickly.
All the best for your scan and I hope you get good news at the end.