High risk following combined test.

....have just found out the the combined test shows a high risk for abnormalities.  1 in 13 to be exact. The pregnancy hormone was 1.67 with protein 0.32 which doesn't mean much to me!! As I already have a son with Down's syndrome - who I love dearly, I'm not sure as I'm strong enough to do it all again.  Haven't stopped crying since finding out!  Why is having children such an emotional rollercoaster!!  Feeling a little fragile at the moment.....