You're not a bad person, you are just being honest. This actually makes me very, very sad and I feel bad for your little baby who is the one actually going through these medical problems. As hard as it is for you, she is suffering as well and needs her mom to be strong. Do you have family that can help you?
I strongly urge you to go talk to a professional because these negative thoughts can be normal, but are NOT healthy so please seek help. You will look back and miss these precious times with your child, no matter how tough they are. Being a parent isn't always all sunshine and roses but really freaking hard so get any help that you can to get through this.