5w5d ultrasound...need reassurance

Re
So I went in for my first appt yesterday and I expressed my concerns on ectopic, blighted ovums etc. I told my midwife I clearly read way too much on the Internet (she agreed). Well I had an ultrasound and she told me not to get upset if I don't hear heartbeat yet because it's too early. My ultrasound showed a gestational sac and a yolk sac, no baby or heartbeat. Of course I left feeling uncertain and now I'm just thinking the worst. Even tho the tech told me I'm measuring exactly where I should be at 5w5d. I go in next Wednesday for another ultrasound. These were my doctors note on it:
Consistent with menstrual dating; live IUP cannot be confirmed. Called patient to go over results and reassured that measurements area c/w her gestational age and that no problems are suspected at this time.
Should I be worried or have any of you had good outcomes with this? I just feel like I can't get excited until it's considered a viable pregnancy.