Ultrasound Cut Off

So I'm a ftm, currently around 27 weeks. I've gotten one ultrasound done since finding out I was pregnant. (It took a while to get insurance and find a doctor.) I got to see my little one and find out we're having a boy at 18 weeks. I've been waiting patiently for a good while for the next time I'll get to see my Little Mister, only to find out at my last appointment that I will no longer receive anymore scans because I am passed 20 weeks. This genuinely broke my heart. I'm not only devastated, I'm also confused. I feel as though there are many other reasons that ultrasounds are useful, aside from just getting to see him. Am I wrong for being so upset by this? Is this a normal thing, for them to stop doing ultrasounds to check baby at 20 weeks? I really don't understand why or how. Can someone explain it to me, please?

I'm not sure where to post this, but I hope this is ok.