Advice please worried

Just had my first appointment with my midwife got really upset as my last af was 12th December and didn’t get my first bfp untill 21 days late had a blood test at 22 days late and my hcg was only 75 the midwife did another pregnancy test today which was a strong positive and has taken more bloods to compare and wants me to have a early dating scan... she seems to think I’m not 8 weeks as per my period date but maybe only 4 weeks has anyone been in the same boat and all turned out well will get my blood results tomorrow