Pregnant and worried???please help?

ok to start with i have a one yr old daughter my partner and i tried for over a yr to fall pregnant with her and she was two months preemie so she is very loved and spoiled and doted on we just found out im pregnant again and we have only just gone off birth control i just dont feel all excited over the new baby like i did with bree and i feel guilty because of it i love and want the new baby but i dont even have time to think about the new baby much chasing bree all day especially when im so tired all the time im just really worried i will have trouble bonding properly with the new baby when he/she is born and wondered if anyone else has felt like this and what it was like after you had the baby????thanks in advance