Mood swings are rapid, uncharacteristic changes in your mood. You may also have bouts of unexplained crying and anxiety attacks.
Mood swings can occur at any point during your pregnancy, but you're especially prone to them in the third trimester.
Pregnancy is a hormonal time and the balance of hormones in your body change during pregnancy. This has a depressant effect on the nervous system and you may feel somewhat similar to how you felt right before your period.
You may also be experiencing a bit of an identity crisis and the changes to your body may not be welcome ones. These thoughts will have a profound effect on you when you're pregnant and your mixed feelings about pregnancy and/or parenthood can influence your moods.
Depression, anxiety, and confusion are common in most pregnancies. Typically, they are nothing to worry about and they don't pose a threat to the baby.