Suddenly nervous

Tomorrow is my Level II ultrasound and Ive been cruising along, feeling pretty confident and not worrying until yesterday. It hit me that I was feeling the same way before my NT scan up until right before the appointment and things didnt end up the way that I had expected them to at all. Im trying to give myself pep talks and not allow myself to go off the deep end with worrying but its so tough. I keep thinking about a girl I know through an internet mom's board that had her Down's stats at 1:750 while mine are 1:532 and they still found that her child had it. The thought of it scares me to death. I try to think about the good things my OBGYN told me, that he is comfortable my baby is OK and has a prominent nose bone which Down's children do not. Im also trying to focus on the fact that if we are lucky, tomorrow we will know if we are having a boy or a girl. I guess to a certain extent its a normal motherly instinct to worry, Im just working on keeping it in check and staying positive. Our appointment is at 11am, please keep me, Todd and our little bug in your thoughts tomorrow. Thank you!