anembryonic pregnancy (blighted ovum)

hi, ultrasound says im 7 weeks pregnant via the gestational sac size. but no embryo found inside it. hence, my OB said that i have anembryonic pregnancy. i have irregular menstruation, but last menstruation period was December 2,2019 up til December 8, 2019. should i consult a second opinion? any thoughts on this?