7 weeks hospital referral

So I believe I'm 7 weeks but already have a belly (it's my 5th pregnancy) unfortunately one of those ended up in a miscarriage at 10.5 weeks... but I bled a couple a weeks ago and thought it was my period.. 2 days after the bleeding stopped ovulation tests showing positive even though I don't usually ovulate till around 20 days after.. done a test and sure enough pregnant... been referred to early pregnancy and they called today and I have an appointment tomorrow.. but as much as I'm exited I'm nervous.. wondering if I won't b as far gone as I thought or that I might b more further along with would b great. Can't wait to c what happens and I'm guessing they will scan me and we can finally work out dates xxx