One measuring a week behind at 7 wks

Hi! I’d love to hear any similar stories and your outcome:

At 7 weeks 1 day sonogram, they saw two sacs. One was measuring 7 weeks 1 days, one was 6 weeks with heartbeat of a 6 weeks baby. Doctor said it’s normal and can still be viable. It’s also possible to lose this twin without even noticing a miscarriage. We will recheck in 2 weeks.

So… did this happen to anyone? What was the outcome? I’m comfortable with any type of story, just reality is all I ask :)