Hi, thanks for the post.
It is always good to have protected intercourse when you are not planning for pregnancy, sometimes there are chances of medications, sexual activity, anxiety about pregnancy can also be the cause for the delay in mentrual cycle. If the period is continuosly delayed for more than 10 days and have early pregnancy symptoms like morning sickness, vomiting, frequent urination, feeling tired, tenderness of breasts, light-headedness, feeling dizzy, getting irritated, and increase sensitivity to smell. There are chances of pregnancy positive result. Kindly consult your family doctor and confirm the status by Beat HCG test.