Pregnant seven weeks two days according to last menstrual period but only measuring five weeks six days

not exactly been through similar (kept measuring about 6 days behind but making gradual steady progress), but nonetheless I'm sending good vibes your way

That genuinely doesn’t sound good. I am praying for you

I measured 3 weeks behind my lmp dates and he consistently grew from there, it just meant i ovulated at a different time than 'expected' (went for a scan when lmp said 11 week's but baby was measuring 8. Now at 41 weeks 1 day awaiting his arrival). At your gestation even a fraction of a millimeter can change the weeks indicator by many days even by a week or more because of how small everything is at that point it's so hard to get the measurements spot on as baby is barely 4-5mm at this point. Which is why it's also very normal not to see a heartbeat yet as their heart is still literally 'microscopic' at this point so it's very normal for the ultrasound to not pick it up just yet.
I know it's so hard and such a confusing time/feeling being so excited and so worried at the same time. Baby is similar size to a pea and there's only so much the tech can do at this gestation 😊 I hope this is somewhat reassuring 🤗

Sometimes the implantation is later so based on your last menstruation sometimes the math ain't mathing... I would breathe in and out and have another appointment in 2 weeks. In the meantime take care of yourself. Everything might be ok it's very early still

Sometimes you ovulate at a completely different time than what is considered normal. Dont worry about tracking it from your period. And also when its so small it can be hard for them to get a good enough picture to truly tell the size or hear the heartbeat. If you have tested positive for being pregnant and havent had a huge blood loss or period type bleed then most likely this is all just happening because its so small. They could barely measure my baby at 13 weeks and didnt get a good look to tell size until 17 weeks.