Second baby

Kaci • Partner’d up since August 2003. My son and moon : 5.4.12//7.6.15
I have asked this question of many women and keep getting the same answer. 
First, let me explain. I love my son (2 1/2). I am IN love with my son. He is my soul mate. I hate every second I am without him and when I'm with him I just stare at the majesty that is...him. I am pregnant with baby #2 (yay!) I wanted my son to have a sibling because I did, and am so happy to. I am 10 weeks and am constantly in fear of what a new baby will do to my relationship with my son. I have cried on it. I feel SO GUILTY. I can't even be excited about this pregnancy because of this fear. Please tell me how to smoothe this addition and transition to a 4 person family.