Early Signs of Pregnancy

Fatigue

You didn't even make it through one page of your book last night before falling asleep. If you're suddenly exhausted, it might be a response to the increasing hormones in your body. For many women, tiredness continues through the first trimester, but then ebbs in the second.


 
Nausea
Most pregnant women start to get the queasies when they're about 6 weeks along, but some can experience morning sickness (which unfortunately can occur morning, noon and night) earlier. It will most likely subside as you enter the second trimester. In the mean time, try to eat foods that will settle your stomach, like crackers or ginger ale.
 
Headaches

More early signs of pregnancy include an aching head, a result of changes in hormones. Just in case you are indeed pregnant, take pg-safe acetaminophen instead of ibuprofen to deal with the pain.

Backaches

Is your lower back a little sore? If you don't normally have back pain, it could mean your ligaments are loosening. Sorry, this one might continue through your pregnancy as your weight gain and shifting center of gravity throw your posture out of whack.


Cramping

Is it PMS or pregnancy? It's hard to tell, but if you're feeling crampy, it might be your uterus stretching to get ready for a baby.

 

Constipation and Bloating

You swear you fit in your skinny jeans just last week. If you're feeling a little puffy or backed up, it might be extra progesterone due to pregnancy, which slows down your digestive system.

 
Elevated Basal Body Temperature

If you've actively been trying to get pregnant, you may have been charting your basal body temp to pinpoint ovulation. Generally, your BBT is elevated from ovulation until you get your period 2 weeks later. If it stays elevated beyond two weeks, it might be because you're pregnant.
 Source:  http://www.parenting.com/gallery/early-signs-of-pregnancy?page=12