I had the First trimester screen, where they test your blood and measure the baby's nuchal translucency. I was given 1:15 odds and we decided to have a CVS for diagnostic testing. Our baby is fine.
What kind of screen did you do? was it the quad screen?
My poor results caused me to research the heck out of the test, something I should have done before getting it. Basically, for the NT test, 1 in 33 women will screen positive. Out of those who screen positive, about 1 in 35 will have an affected pregnancy. The older you are (I am 35), the more likely you are to screen positive. For my age group, it's 1 in 15, but the ratio of women who have unaffected pregnancies is the same. I've read that false positives are even higher for the quad screen.
something else I found out is that vegetarian women have been found to have naturally high levels of free beta hcg, one the proteins they test in the First screen (not sure if it's tested in the quad screen), so it throws off the results and automatically increases your chances of screening positive. High hcg and low papp-a are found in women whose babies have Down Syndrome.
Anyway, I've read tons and tons of stories of women who received poor results from their screening and went on to have an unaffected child. I really think the odds are in your favor. I know it's hard to relax after being given your results, but I hope you can.
The good thing about an amnio is that it can give you time to prepare for any outcome. I'm not advocating it, just pointing out that it has advantages and isn't meant only for parents who would terminate...