Ive been 6 weeks pregnant for 2 weeks now

Ok so based on my lmp i should be 8 weeks day 3 i went for an ultrasound on jan 21 and all they saw was a yolk sac inside the gestational sac and was measuring 6 weeks based on this and the fact the the gestational sac was measuring 13mm.  Today, one week two days later,  i went for another ultrasound and they saw a tiny fetal pole and a faint hb and told me based on crown to rump measurement i am 6 weeks pregnant ehich would put my ovulation date around new years <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> dec 31 BUT i got my first positive hcg and home pregnancy teat two days before that on dec 29.  I still havent rwceived an estimated due date ecause they want me to get one more ultrasound next week.   Anyone else experience anything like this?