What Could Be The Cause Of My Missed Period After Taking Diphoton 10 For 40 Days?

Hi, i have problem with my periods (irregular) Dr. prescribed for me Diphoton 10 for 40 days. i started taking it on the first day of my period (5/12/2022) and it got finished on 23/1/2023 but till then i have not receive my period yet. i tested for pregnancy but the result is negative. what could be the issue.