With the list of symptoms of pregnancy to contend with, and a body that is changing daily it is perfectly normal to feel irritable and experience mood swings. Beyond the physical changes, there are emotional changes you are dealing with even if your pregnancy is well planned.
Your moodiness can be pinpointed once again to the hormonal changes in your body. Mood swings are very common during the early part of pregnancy, and unlike some symptoms of pregnancy they will disappear fairly quickly as your hormones adjust.
Bursting into tears for no outwardly logical reason, emotional outbursts at the smallest slight even most pregnant women don't understand why they are feeling the way they are which can make them feel worse! Mood swings are totally and completely normal. Talk to your doctor as always to let him or her know of your symptoms, sometimes just having them reassure you that you're experiencing what many women before you and many women after you have gone through will comfort you.