anybody had first scan at 4.5 weeks ? I had n m worried hell !! pls help

Mikki
Hi ladies ,
Had my first ever scan yesterday , I was assuming that I'm 5.1 weeks but scan said I'm 4.5 weeks 
Just seen the sac, 9.2 MM and empty !!
Have follow up scan on 04/15.
I'm so worried I thought there would be atleast yolk sac there, also I read on Google that @ my diameter sac should contain yolk sac as well else the pg is not viable!! I hope I'm not at loss!! These two weeks would be killer!
Pls pray for me n my baby!! 
Anyone there been at my situation?! We are trying since very long! I don't want to get disappointed!!
Pls help !!