Hi,
I had a down syndrome scare as well during my pregnancy. Doc said high risk and asked me to go for amnio but i wasn't willing to risk the chance of a miscarriage. We ended up seeing this indian doc (can't remember his name) at Camden Medical Centre, did a very detailed scan where he measured every single part of my baby and told me that he will quit if my baby is born with down syndrome. The scan cost $500+ but it put my heart at ease.
Go google it and decide if you wanna see him? But i definitely advice you to get a 2nd opinion cos there are really a lot of false alarms...and the worst is to have you really upset and have a healthy crying baby.
Take care!