Hahaha fannycam! 
Thanks dietcoke! Very reassuring... which I need as my reassurance scan has left me with precisely NOTHING. I'm in limbo thanks to my GP not really understanding how/when to book scans.
Basically got there this morning, did the usual maths (last period, length of cycle etc') and the consultant said BEFORE anything else "well, at this stage many pregnancies don't show on an ultrasound yet, your GP should have booked you for 2 weeks time [ yeah I KNOW but my locum GP didn't know the systems for booking non emergency EPUs ] and if we don't see anything we'll have to call it a PUL and you'll have to do 48 hour bloods." To be honest, I wish they'd just done the bloods!
So they do the scan and lo and behold - they can see some indistinct dot which could be a sac or could be a clot or bubble or something. The junior doc is getting all loud with words like 'ectopic' and 'miscarriage' and I am freaking out a bit- he keeps asking if I'm SURE I don't bleed or have pain (BH calls this 'spotting zebras on a horse farm' ... trainee medics looking for something rare and exciting to them). The consultant is less freaked out and calmly and firmly reminds me that as he said OFTEN at this stage they can't see enough to reassure and my GP booked me too early. The upshot is, they have taken bloods and will take some more on Sunday.
Will get a phone call later today with today's hormone scores then have to go back to the 24hr urgent care clinic Sunday morning (Consultant told me to tell them not to get all over enthusiastic and try to re-scan me or anything but just take a bit of blood lol spotting zebras again). By Sunday night I will know: normal pregnant, not pregnant or (unlikely but they must test) ecptopic. 
Well, I've not had one sided pain and I haven't bled and I feel sick... fingers crossed it's option 1, and the sac is just too small to see yet.