What Causes Change In Menstrual Cycle Pattern?

Hello Doctor!

This is a gynelogy question. My periods have become shorter.My Periods are starting once in every 21 days, regular. Before it was 28 day cycle.

I am becoming tired, I look anemic with severe leg pain before periods. How can it become 28 day cycle?

I really appreciate for your kind suggestion



Thanks & Regards.

S