2 weeks behind with very low heartbeat... how bad is this?

Frances
Help! I had my first ultrasound this morning, as I was supposed to be eight weeks today. Instead, my baby was measured at only 6w1d, and also with a particularly low heart rate of only 82bpm. I'm really afraid this is more than a miscalculation of my dates, and that it's actually that his/her development stopped at six weeks and that the heartbeat won't last much longer either. I've been referred to the early pregnancy unit in the local hospital, but they haven't booked me in yet, and apparently it's likely that they won't see me until next week at the earliest! Has anyone gone through anything similar? If so, how did it work out for you? I'd like to hear both good and bad, so please let me know, whatever the outcome. I think it'll help give me a little hope, but also prepare me for the worst, in case that is what's going to happen! I can't stop thinking about it... This wait, not knowing what's going to happen, or what I can possibly do to help him/her survive is just torturous!