First Ultrasound - Not as Far Along as Expected

Brittney
So I had my first 8 week ultrasound yesterday - based on the size they told me that I am not actually 8 weeks, I am more like 6 weeks. I have irregular periods - that's why they thought 8. Kind of a bummer to be honest...but we were still able to hear the heartbeat which was pretty cool! 
Anyone else have this happen to them?