Mood swing while pregnant.

Premenstrual syndrome and pregnancy are alike in many ways. Your breasts swell and become tender, your hormones fluctuate, and you may feel moody. If you suffer from premenstrual syndrome, you're likely to have more severe mood swings during pregnancy. They can make you go from feeling happy one minute to feeling like crying the next. You may be irrationally angry with your partner one day, then a coworker may inexplicably irritate you the next.

Mood swings are incredibly common during pregnancy, although they tend to occur more frequently in the first trimester and toward the end of the third trimester. Hormones can and will do crazy things to you for the duration of your pregnancy. And once your little one has arrived, do not be surprised if you don't just snap back into your old self. Once pregnancy is over, your hormones will need even more time to adjust back to normal. I would be comfortable saying almost all women get the "baby blues," an overwhelming sensation that is multiplied by lack of sleep, lack of independence, and increased by all the new feelings that comes with taking care of someone else 24/7. Literally 24/7. Just because baby is asleep, does not mean a woman's worries of her precious new responsibility ends. 

Some women experience depression during pregnancy too. If you have symptoms such as sleep disturbances, changes in eating habits (a complete lack of appetite or an inability to stop eating), and exaggerated mood swings for longer than 2 weeks, you should talk to your doctor.