Hello, I have gone through your query and understood the concern. You did not mention if you read positive for pregnancy test prior to this. If you had a confirmed pregnancy through a pregnancy test yet no sac is visualized, the possibilities are that the sac may have been expelled early or not yet made out. Ectopic pregnancy can have symptoms like bleeding, pain- abdominal cramps, lower abdominal pain, pin in tip of shoulder or neck or rectum, weakness in extreme limits etc. Diagnosis is made by history, careful clinical exam and sonogram. Your symptoms are not likely to be due to this. I would ask you to get hormone profile to detect any imbalance and henceforth correction. Hope this helps.