Help me find out how far along I am

I miscarried November 13th and found out I was pregnant again December 6th. I went to an early ultrasound yesterday and she said it’s measuring less than 5 weeks because of the size of the sack and how we can’t find a heartbeat yet so I’m going back in 2 weeks. I’m pretty sure I conceived November 25th and if I use my mc as a last cycle I’m glow it says I’m 5 weeks 6 days. Please clear this up somebody I’m very worried about my baby’s development or that it will happen again 😞