Period is late over 5 days. had sex with a condom on the day period was meant to arrive. back pain & small abdominal cramps for days but no blood?

Condoms work, but...: In one with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing a doctor is a good idea if symptoms are persistent or worrisome. Pregnancy is a common cause of a missed period, if having sex. Can do a pregnancy test.