AF start-stopping with breastfeeding?

Amanda
I can't believe I'm even asking this, but today I went to my OB's office for a PT (AF is a week late, I've had intermittent cramping, my supply has dropped a bit)... 
The PT urine test came back negative, and I'm waiting for the blood work results.   When I asked the nurse there what the next steps should be since my period has never ever been off by more than a day, she looked at my 15 month old son, asked if I'm still breastfeeding, and then said "well there ya have it."  Despite explaining to her that I've consistently had my period for the last year and he is in fact nursing less, not more, she looked at me like a moron.
So, is this a thing that anyone else has experienced , or is she the moron? 😜