Having a second baby

I have always wanted 2-3 kids. We have an almost 3 year old and are having to go through fertility treatments to try for our second. But now I start to worry what it will be like with a second baby. I work from home but have so many moments of special time with my daughter, from playing with her, reading her stories, snuggling in bed when she wakes up in the morning and calls me in there. I don't want these moments to stop or her feel neglected when my attention is split between her and a sibling. I know there will be new special moments, but I still worry. What was it like for you?