when is the soonest you can see the baby on the ULTRASOUND??

when is the soonest you can see the baby on the ULTRASOUND?? My doctor didn't see nothing yet and she thinks I'm 5 weeks and 6 days and I had blood  wrk Tuesday which my hcg levels were 2050 and I had it done again today and it was 4160 so it's doubled but I'm asking because, I'm high risk for ectopic pregnancy and I don't have kids and it was a miracle I'm even pregnant. should I be worried or it can be to early to see my baby? I feel fine and no pain at all just Normal pregnant symptoms tired ,nausea and really bad breast tenderness lol