My baby's growth and development

I want to share my baby's development. She is 13 days old now and growing. My husband and I were very surprise on her growth and development. On her first week, she was able to lift her head by herself. We are so impressed and proud parents because our child has a fast growth and development. On her second week, she starts rolling on her side already. Oh I am so proud of my baby. I can also see that she is gaining weight because she is getting heavier whenever I am holding her. I am just worried though because we just started giving her some formula milk aside from breastfeeding as a supplement to give her enough milk. Doing so had her having a hard time pooping. Oh I hope my baby's bowel movement goes back to normal and hopefully her digestive system will get use to formula already.