If you find yourself in a hibernating mode for the most part of the day, chances are that you might be pregnant. Do not be alarmed if you are on the edge of tiredness. Though precise reasons for pregnancy fatigue are unknown, doctors connect it to the higher than normal levels of hormones such as progesterone. This is what happens at the beginning of pregnancy. As you will advance into the second half of the pregnancy, you will feel energetic and full if strength again. Take advantage of your second trimester and power up as your tiredness will make its way back by the end of your third trimester.