Postpartum baby blues

Hey so I just had my baby 4 days ago and I am feeling so down. I feel sad I’m no longer pregnant because I feel useless again. I feel sad to know that my little baby is going to grow up (even though that’s what I want of course I love her more than anything) and I feel sad at the idea that if we decided to have another baby that it wouldn’t ever be as special as this one, the pregnancy and the baby. Did anyone else ever feel this way? Does it get better? Please help me.