PZ, I am another one who has never had a mc but keeps having the exact same thoughts this time. Can't help thinking like you, that when I get to the 12 week scan there will be nothing there. Having had losses before of course you will be worried, it's only natural. I have a friend who had 4 early mc's before her current pregnancy which is well into the second tri now. She kept saying she was 'crazy' because she was so worried about losing this baby. But it's not crazy it's perfectly normal - if something has happened before the mind can't help thinking it might happen again. Unfortunately some anxiety will go with the territory. All you can do is seek reassurance where you can (tashy's suggestion sounds excellent) and enjoy your pregnancy as much as you can.