2wks behind

Rose • Fur Mommy 💞🐶🐶

Ssoo according to my missed cycle, I should be 17wks. buutt baby is measuring 15wks. which I knew, because of the er I had gone to told me so. Should I be really concerned? I heard heartbeat and it's 164. But now I can't get this off of my mind. Anyone else dealt with something like this?