Good luck for today jaqueline thinking of you and hoping you get some reassurance today. I know nothing apart from hearing and seeing baby's heartbeat and feeling movements will help but my 16w appt was fairly similar to yours (pulse from placenta heard clearly) and they've just said I have an anterior placenta on 20 w scan.
mama the bf thing makes perfect sense to me and knowing how determined you are try to take some solace in knowing you will give it your absolute best shot which is half the battle with these things (persistence). You are an inspirational mother!
missmuffet I think all the advice has been given but I would say you might need to think about slowing down at work by the sounds of it.
Good luck to all of you having scans today.
My scan with the consultant went really well yesterday, phew! 
He was very thorough and got the heart measurements needed and we even saw the coloured blood flow (hope that makes sense). He then spent a while going through everything with us, all organs etc. Baby still camera shy so still haven't got a decent piccie! Might invest in a 3d/4d scan if you ladies recommend it. Just worried we'd spend all that money and still have a camera shy bump! We're having a surprise!
PS one of my friends relatives in america got their sonographer to tell their baker (I know I know, but this was LA) the sex of the baby. The baker then made them a cake which was either blue or pink inside and they had a revealing party with their family where the cake was cut. hehehe! How totally over the top and memememe is that! I think I might actually love it! Not that I would ever do that (I mean my baker knowing before me hehehe).