Is It Normal To See Only A Gestational Sac Without A Yolk Sac Or Fetal Pole At 7 Weeks?

Hello doctor... My LMP was 5th March 2021...my cycle length is 31days...i did my first scan on 23rd April... Gestation sac size is 4.5mm whereas yolk sac and fetal pole not seen.... Cervical length is 3.4cms....is it normal or anything to worry... I had my last termination on oct 2020..this my first pregnancy, so little worried