Rotobay and piggypebs:
You are still early in the testing. Rotobay: you tested when you were embies were 9 days old. I tested BFN on 4dp5dt but then received a BFP the next morning which became even darker that eve. So, you could be completely shocked tomorrow. MOREOVER, part of the reason my DE thinks I have twins/triplets is because I tested BFP with 10 day old embies (he thought this was soon). Your window is really about 9-13 days (based on age of embies regardless of transfer date) so keep your chin up. I know you are scared -- as was I when I tested BFN on my 4dp5dt.
Meleson: Mu U/S isn't for another 2 weeks!!! What is it about these 2 week waits (they suck!). In any event, I won't be able to confirm multiples for certain until such time. I know my RE is VERY CONFIDENT that I'm carrying multiples (and I certainly hope he is right), but I have heard stories of very high Betas with only singletons. We shall see.
My next beta is tomorrow (the day originally scheduled for my testing). If all goes well, it should be around 560 or so on 14 day old embies.
No morning sickness yet -- but very tired and get a few dizzy spells. Also, DH says I already have a bit of "pudge."

Oh well, it's all worth it!