Your breasts are now twice their normal size.
One of early trademarks of pregnancy are sensitive, sore breasts. This is caused by an increase in level of hormones. However, this too will pass. Once your rising hormone levels have stabilized and your body adjusts, tenderness will diminish. You should be feeling much better after first trimester.
The monthly visitor has failed to visit.
This actually isn't one of best signals that you may be pregnant. You may have some spotting due to implantation bleeding (although this is uncommon). Most women notice other symptoms before this one comes along. A pregnancy test is usually your best bet.
You suddenly crave apples and pretzels (or any other unusual food for that matter).
Many women claim to crave certain foods during pregnancy. Food aversions are also very common. You may want to take a pregnancy test if your favorite food no longer lingers for your attention.
Your mornings are often spent over toilet bowl (morning sickness strikes again).