My period is 5 days late and I took a pregnancy test and it showed 2 lines, one dark and one light. During this time, I felt a dull pain in my lower abdomen and often more pain on the left side. The pain only comes and goes. Doctor, can you tell me if my period is late and I have a dull pain in my lower abdomen? And how long after my period is late should I have an ultrasound to see if the fetus has implanted? Is my condition dangerous?