Soon to be mom of 2

Just found out I'm pregnant with my second baby. My first daughter is only 5 months old. I feel so selfish for being pregnant again, I feel as if it's not fair to her. She needs all my attention and now she'll have to share it with her sibling. Is it normal to feel this way? I tend to bottle up my feelings about the subject....Ladies please let me know of this feeling is normal!!