Ultrasounds!!

I had my first ultrasound around 8 weeks, then another at 20, and now my third is tomorrow at 32 weeks. I did have one at 25 weeks bc I went to the hospital due to bad cramping and back pain but they weren't too focused on baby and it wasn't high tech or anything. Is it normal to not have a lot of ultrasounds done? I know about 4 other girls who are pregnant and they've all had more then me. The reason I was told to schedule this third one was bc soon after my 2nd one we found out I'm at risk for preterm labor due to high hcg levels, so we scheduled a growth scan. I just hate never seeing my baby and wondering if it's common!