Five weeks is a common time when moms-to-be find out they’re pregnant (though some won’t discover it for a couple more weeks still). That’s because by now you probably realized you’ve missed your period. Plus, heightened pregnancy hormone levels may be giving you some symptoms that are tough to ignore, like sore breasts, nausea and fatigue. (Those same hormones are the ones your pregnancy test picked up to give you a positive result.) These are just the beginning of the slew of changes your body is about to go through. No need to worry though: many moms-to-be say the first trimester was the toughest part of pregnancy, so you’re probably getting the rough stuff out of the way early. In the meantime, be sure to take care of yourself and get plenty of rest, eat right and test out some ways to deal with the queasies (eating small, more frequent meals is one good one). 

 your baby's the size of an apple seed! 

your baby at 5 weeks 

• The embryo doesn't look like much more than a tadpole right now, but at five weeks, she's already starting to form major organs (heart, stomach, liver, kidney) and systems (digestive, circulatory, nervous).

pregnancy symptoms at 5 weeks

• Those same hormones your pregnancy test picked up are likely starting to rear their ugly heads, causing some (not so fun) early pregnancy symptoms. The most common? Sore breasts, nausea and fatigue.
• You might also notice yourself having the urge to pee frequently early in pregnancy because of expanding kidneys.

-your must-do's

• Remember to take your prenatal vitamin.
• Schedule your first prenatal OB appointment.
• Confirm that any prescription drugs you're taking are safe during pregnancy.
• Stop drinking. Alcohol during pregnancy is a big no no.

-your nice-to-do's

• Start a pregnancy diary, to track your thoughts, feelings and baby's growth and movement. 
  

 Source: pregnant.thebump.com