8weeks after LMP, Yolk sac has disappeared

Hello po, May same case po ba dto. 8weeks na po since my LMP, pero until now 5weeks palang sukat ng gestational sac ko. Last week may yolk sac na po, pero ngayon nawala yung yolk sac. My OB gave me 2weeks more, pag wala pa daw po raspahin na ko. Please let me know your thoughts or experience.