Nice to hear from you fleur, and TOTALLY understand your freak out.
I did a quick Google and found this, hopefully it helps you. It sounds to me it's the increased estrogen thing, but hey, if you're not sure, call your midwife, you are so entitled to freak out and call her whenever you need to, jeepers, she should be at your beckon call (hmm, is that right? beckon call, or is it back and call, or something else completely, totally OTT).
Anyway....
http://www.babycenter.com/0_vaginal-dis ... ncy_270.bc
So anatomy scan aye
How did it go, did you find out what you're having