1st U/S yesterday-only yolk sac normal?

At my first appt they estimated my due date around 2/2. Went in to have my first ultrasound yesterday and saw the yolk sac, but couldn't see the baby yet. The dr wasn't concerned at all and scheduled me for July 7th and said we would've able to see the heartbeat and baby then. Is this normal? When they 1st told me my due date I kind thought it was a little soon because that would've put me getting preggo a couple days after AF. All my bloodwork was normal and my HCG level was 5000 last week. He said everything looks normal, but just worried until I see that little baby. Thanks ladies :)