Hate saying this

I found out I was having twins about 2 weeks ago, I've been so shocked and nervous. I had another appt today and they are growing great and have strong heartbeats. I can't seem to get excited, everyone around me is thrilled and I just say yep. I don't know what's wrong with me?! I have a 1 year old now and she is my world, I am so worried about her feeling left out. Please tell me i will get excited because i know I'm extremely blessed, I'm just absolutely terrified right now.