If your period is 4 days late and you have cramps, you could be pregnant, especially if you had unprotected sex around the time you were ovulating.
Mild cramping can happen before a period or in early pregnancy, so it cannot confirm pregnancy on its own. Other early pregnancy symptoms may include nausea, bloating, breast tenderness, and fatigue, although they often become more noticeable around the fifth or sixth week of pregnancy.
You can take a home pregnancy test now. If the result is negative and your period still does not start, repeat the test in a few days because testing too early can lead to a false-negative pregnancy test result.
Short delays can also be caused by stress, illness, weight or exercise changes, hormonal birth control, or normal cycle variation. See an OB-GYN if your period remains late, delays happen often, or your test results are unclear. Seek urgent care for severe or one-sided pelvic pain, shoulder pain, fainting, dizziness, or heavy bleeding.