HELP! Early scan measuring less 😭

I had to go to the Early pregnancy assessment unit this morning due to cramping and slight pink discharge when wiping. They said the pink was nothing to worry about - I have cervical ectroption and it was coming from there.

They did a early vaginal scan… and I thought I was 6 weeks 4 days pregnant (based on using OPKs) and the doctor dated me at 5w6d… so 5 days behind. She also said it was too early to see a heart beat, but could see a nice gestational sac and yolk sac and the start of the baby (but it was tiny). I have to go back in a week to check everything is progressing normally. She seemed quite unconcerned with what she saw.

My questions are:

Is it normal for a early scan to show 5 days earlier than expected? Even if using OPKs to pinpoint ovulation?

Is it normal not to see heart beat at 5 weeks 6 days?

Please give me some reassurance 🙈😭