Me too. My scan is tomorrow and today I woke up so nervous I don't know what to do with myself!! Like you I can't stop thinking what if something is wrong.
I got a doppler from ebay which hardly cost anything but most baby stores sell them which would probably be better for you because you might not get it from ebay before your scan. Try blooming marvellous if you have one near you and mothercare do them too.
Must try to relax..........
