From last 4/5 days i am having pain in lower back and lower abdomen. Today is 28th day of my cycle but still i didn't have my period yet. This pain happens throughout the day. Its very sharp period cramps like. I have not tested for pregnancy yet. Should i do that with HomeKit? May date is 25th but usually i have my periods between 26th to 28th day. I am scared it never happened with me like this. I was having letrozol on 3-7th day of cycle from last 3 months. Also having folic acid tabs regularly. Please help. This back and abdominal pain is hurting a lot.