HCG levels and missed miscarriage

Hello all .. going back for a second ultrasound this week, two weeks after my last when I measured at 6 weeks and no fetal heartbeat. I’ve had no cramping or spotting, but am mentally preparing if baby hasn’t grown. I’d assume my hcg levels would have dropped a bit by now seeing its been two weeks if this is the case, however my pregnancy tests are still coming out super dark - always taken with first urine of day - and darker than control line dark. I’ve seen many hopeful stories of 6 week ultrasounds without heart activity that went on to have healthy pregnancies but just prepping for the worst. Any one with any advice for me at all? Thanks so much :)