I had unprotected sex with my boyfriend after 5 days of ovulation (i didn't take a emergency contraceptive pill considering low chances of pregnancy). Later, After 4 days I had yeast infection (vaginal itching and curdy white discharge) for 4 days which got cured by itself (i didn't go to doctor or didn't take any OTC medicine). After 2 days We had sex again but the condom broke. I didn't get my period on expected date. So, I waited for a week and took UPT (with I can pregnancy kit). I followed all the instructions carefully and took all the measures to prevent false result and the result turned out to be negative (only a single line at C). If I am not pregnant. What could be the reason for me not getting my periods yet?