Hi there - with my history I was having an ultrasound every couple of days when I was first pregnant this time around - as I had a massive bleed and was in hospital for a couple of weeks. My best friend is a OB Sonographer (performs ultrasounds) and she claims that there is no harm for baby or mummy. I tried to have a CVS test at week 12 but could not due to the position of the baby - so I waited for 4 weeks and had an amniocentesis (to test for DS etc) (which incidentally did not hurt, the Dr was so good, she distracted me talking and I was asking her when she was going to start and she had finished!! All I felt was the initial local anaesthetic going in...) The results of the amnio were fantastic - another girl who is just perfectly fine!! Best to placate you and find out all is fine with baby and then you and baby will be more calm and relaxed.
Good luck! \/