Thank you ladies :) it is just hard to wait for these things that make you so worried.
It's possible too, that it's from how the baby was sitting. It happened with my now 4 year old daughter. They did one and it showed hardly any! The next time they checked, the next day I believe, everything was normal because she had moved. The angle she was at, made it look like she took up more space or something so her levels measured low. Scared the poop out of me though! Hope it is just that!!!!
They'll probably monitor you closer now. Drink more water to keep your levels up. I'm sure everything will be fine :-)