You must be feeling so confused.
My experience was similar - 1 in 125 down's likelihood with ds 1 and 1 in 250 with ds2. I didn't take things any further - no CVS or the thing that I have totally forgotten what it's called and they put a needle in and test the fluid.
The blood tests are extremely inconclusive, and not reliable at all.
The chance of miscarriage with a CVS or needle thingy (it'll come back to me, the name!) is 1 in 100 or less - worse odds than your baby being downs.
Having told my consultant why I was just going to accept the result of the blood test and not act upon it he told me that in my position he would have encouraged his wife to do the same thing.
I knew in my mind that I would not terminate my pregnancies if the babies had been DS, so there was no need to take further tests.
Please don't fret about this blood test result - speak to your consultant, and think about what you would do in the (extremely unlikely) event you discovered your baby was DS. If you would keep the baby then I would put it to the back of your mind and enjoy the pregnancy.
In this situation you will find that they are extra careful about looking for downs markers at your 20 week scan. I found this scan hugely reassuring.
Neither of my ds's have downs, despite the rotten odds that I had.
One midwife told me 'whether you have a result of 1 in 2500 or 1 in 100, everyone has the 1'. The test is useless, they factor in your age when working out the results and so as you get older your results get worse automatically, nothing to do with what they find in the blood.
Please please don't fret. Remember that you are 109 times more likely not to have a baby with DS than you are to have one.
Hope this helps.