It is not at all uncommon to experience pregnancy fatigue. It seems only natural that sustaining two lives drains you of more energy than only dealing with your own. Having a fetus growing in your belly most certainly takes its toll on your body. Pregnancy fatigue is often accompanied by a multitude of aches, pains, and sore muscles. How you deal with these problems will often determine your level of pregnancy fatigue. Pregnancy fatigue is generally caused by your body adjusting to natural hormonal changes, and the added weight of carrying the baby. You may also be having trouble sleeping due to aches and pains, vivid dreams, or simply too much stress.