Nausea, or morning sickness as it is commonly known, is another classic pregnancy symptom. Morning sickness is actually a misnomer, since the nauseous feeling can (and often does) occur at any time during the day. It usually starts in the first 5-6 weeks of pregnancy, but can be felt as early as two weeks after conception. While certainly unpleasant, the good news is that morning sickness tends to fade away at the end of the third trimester.