No heartbeat?

Mellise • ~BFP August 2016!~ 👶🏻💙 (used pre-seed.softcups.opks) Pregnant with #2 Due Jan,11,2019
A bunch of ladies on this app already saw a heartbeat in week 5. This was taken 5 weeks + 4 and she only saw the yolk sac. I'm worried now 😢