Only 2 ultrasounds thru whole pregnancy??

I've only had two ultrasounds and am 34 weeks. My doctor said I won't be having anymore. Is this crazy or is it just me? I had one confirming the pregnancy and the anatomy scan at 25 weeks. 
I don't understand why there wouldn't be at least one more to see if any abnormalities have formed over the last few months. Am I alarmed over nothing?