Missed Miscarriage?

March 8th I went in for an ultrasound and all they found was a sac.

I just went for one yesterday (April 14th) and he said the baby is very very tiny. To small to see a heartbeat, and to check with my doctor in a few days for the results of the ultrasound.

I’m freaking out..is this a missed miscarriage

I have no idea how far along I an supposed to be. I haven’t had a period in a very long time because of an IUD.

I took my first positive pregnancy test February 23rd.

I’ve never been fully able to grasp all the conception concepts and stuff, but to what I understand the dates just don’t line up to there not to be a heartbeat so I’m really panicking.