First appt question

So I had my confirmation of pregnancy on Christmas <a href="">Eve</a> and they wanted to see if they could see anything....saw a heartbeat and they said looked 6wish and then wanted another ultrasound in a week or two. Is that normal? I feel like two ultrasounds in two weeks is excessive and I still don't have a due date. I'm just concerned that they want me back so quickly because something may be wrong. Any ideas, hoping I'm just paranoid