There are other signs and symptoms of pregnancy. You have mentioned two of the most common and the most obvious, an absence of menses. However, you should also remember that early morning nausea and the lack of menses can also occur with other conditions not associated with pregnancy.
Many women ‘just know’ when they are pregnant. These women seem to have a sixth sense that alerts them. Also, breast tenderness and breast enlargement are symptoms that are associated with early pregnancy. In addition to these, many women will feel fatigue early in pregnancy that may last into the early second trimester.
By all means, if you think you are pregnant do a home pregnancy test to confirm your suspicion, and see your physician so that you can begin prenatal care early.