Where did my quiet baby go?

Sophia, my 2 year old, was an absolute dream of a baby. I was actually alarmed when she slept nearly all day every day for the first 3mths of her life. I kept waiting for the other shoe to drop, surely THIS would be the night she kept me up. Never happened. She's never been sick, not once, and never taken an antibotic. She was so quiet.

Then she hit two. I am not sure what happened. The month before she hit two I was on bedrest for my 5th pregnancy and my MIL was staying with us to help. The week before she turned two, my youngest was born. That was the first time Sophia had ever spent without me and it ended up being 2 nights. When I arrived home with Delilah, Sophia was beside herself. For three days there were tantrums, lack of sleep, and anytime I left the room I heard screams of "Mommy?!" I didn't expect her to change so much in such a small period of time. My other two girls transitioned easily into big sisterhood. Of course Lilly was 2yrs 7mths when Aidan came home. She is also not a "mommy's girl" she is very independent and very mature for her years, always has been. Aidan was 3yrs 7mths when Sophia came home from the hospital. She is a mommy's girl somewhat, but still very independent. Sophia was just 23mths 3wks when Delilah came home and all hell broke loose.

I still can't decide what "did" it to her. She has settled in and the only way she expresses her jealousy toward Delilah is when someone is holding the baby she runs up and says "I hold her?". She knows that the person holding the baby will be helping her "hold" the baby by holding her in their lap. One smart cookie. The only real complaint I have now about her 2yr old self, is volume control. I also have had this same problem with Lilly since she was a baby. There is absolutly no controlling the volume of their voices. They always sound like they are yelling at you.