Ultrasounds? how many is too many?

Julia
Hey everybody! 
My husband and I are pregnant! Yay! 
Second pregnancy! First was a missed miscarriage. Technically I am not high risk.
I had an Ultrasound at 6 weeks in the US (but the sac didn't measure 6) 
Then I went to Germany to visit family for holidays. Two weeks later I had another US in Germany to check if anything has grown. Thankfully baby was meassured at 7+ weeks. Heard the heartbeat 
Today, after another two weeks I had another one because the doctor (my mom's friend) said if we wanted to see how much the baby has grown then we can come again. Which of course we wanted. We heard the heartbeat again. I'm traveling back soon..
But now in another 10 days I need to get blood work done back in the US and an ultrasound is also scheduled. Which I don't know if I should do or not.. 
I am a first time mom, just trying to read some opinions. I know usually women get only 3 ultrasounds total if not high risk. And I already had three and I am only 10 weeks pregnant. 
My husband is saying it's fine and I shouldn't worry but I am thinking about canceling the coming up ultrasound. 
Have a great day ladies and thank you for your help!