Fatigue is by far the most common complaint during the first trimester, says Roger Harms, MD, editor of The Mayo Clinic Guide to a Healthy Pregnancy. Aside from the simple fact that building a baby uses a tremendous amount of your body's resources, you can also blame a steep increase in the hormone progesterone, which is known to have a sedating effect. The extreme sleepiness usually tapers off by eight to 10 weeks and rarely lasts beyond 13 weeks.
Feel better fast: The most important thing is to slow down. Take naps, go to bed early, and let the housecleaning slide for now. You should also continue to exercise -- though you may need to cut back on the intensity of your workouts. In addition to helping you tolerate pregnancy and labor better, exercise can actually increase your energy level, says Terry Hoffman, MD, an ob-gyn at Mercy Medical Center in Baltimore. Not used to working out? Ask your doctor if it's okay to start a simple routine, such as walking for 20 minutes a day.