Heart problems?

Bree • Baby girl born 6/30/15 Twin girls born 3/3/18

I went in for my 20 week prenatal appointment yesterday and told my doc that I have been having a heard time catching my breath and that I’ve had very little energy. I’ve been assuming it had something to do with my iron levels. With my first pregnancy I was very anemic and this felt similar. My doc did blood work and found all my levels to be perfect. He then did an EKG in the office and scheduled me for an echocardiogram. I’m a little nervous now because he hasn’t said anything regarding the EKG. The echo isn’t until next week but I would think if something was wrong he would have said something?? Anyone else have this happen?