I know it's due to the hormonal changes, and I've seen that already at 5-6 weeks now. I know I shouldn't take it personally, but it is hard. Moodiness is very common during pregnancy.
Some women are more moody than others.
There is some research evidence suggesting that women who were somewhat anxious or depressed before pregnancy might have more intense mood swings during pregnancy. I have three suggestions. First, try to look at her moodiness in a positive light. Her moodiness is one of the many frustrations all parents will experience raising kids. Try to smile when she is moody.