When to take pt

Supposedly mentruation ko is march 15 pero until now hindi pa ako nagkakamens. No sypmtoms yet na magkakaregla na ako. But I'll wait unti april 15. Nakatakot kasi mag pt baka kasin negative na naman?. I took pills to regulate my mentruation last feb 2018 good for 3 montha yun. After taking those pills, pagka december 2018 hindi na naman ako niregla. January 2019 na ako niregla ulit. Pero mga september the same year, hindi na naman ako dinatnan tapos i had my period october na naman. Tapos ngayong march yung hindi pa. Baka delayed lang kasi stress??