Confused about misscarraige

I had a private scan on 11th August and they said they can see one baby and I'm around 6weeks 2days. Flicker of heartbeat.

I've been fine since....

I started getting some brown spotting with my discharge on and off for the past week.

I should be 11weeks 1day today and went for another scan where they saw a baby and they said its measuring 6weeks 3days, but no heartbeat.

They are saying I have lost it.

But my question is how can I go more than 5weeks and have no bleeding or anything 😪😪 I can't get my head around it😪