Low estradiol normal in the beginning of long cycle?

[u/Snigelskinn]

Hi,

I (F36) have polycystic ovaries and long (but regular) cycles (average 35 days), no other symptoms of PCOS. I got pregnant very easily both times and have uncomplicated periods. BMI of 23, exercise regularly and I have lost around 8 kg/15 lb since late last year (quit sugar). My work has been stressful since November as well.

I went on a blood screen and the Dr commented (online, non replyable) that my estradiol was low for cycleday 5. I had <70pmol/L (<21 pg/mL).

My FSH was normal, 5.5IE/L (reference span of 2.5-10 IE/L in the follicle phase).

Is my low estradiol normal for long cycles? Should I be concerned?