Progesterone dropping/fluctuating early pregnancy

Hi everyone. I’m currently 5w2d. I got bloodwork done at exactly 4 weeks and exactly at 5 weeks and my progesterone dropped.

4 weeks- hcg: 84 & progesterone: 19.1

5 weeks- hcg: 2510 & progesterone 12.8

Is it normal for progesterone to drop? I haven’t seen an OB, so they won’t take me until my first appt at 9 weeks. But on the phone they said that the doctor doesn’t look at progesterone. Since my hcg is rising it’s fine.

The nurse practitioner at my doctors office that originally sent me for my bloodwork is out and can’t send me for more today.

Note: @ 4 weeks i hadn’t eaten lunch, hadn’t eaten since breakfast - it was about 11:30. @ 5 weeks i had just eaten a bagel for breakfast. Not sure if that makes a difference.

Should i be worried about the drop?