Maddie at 1 month

I took Maddison to her 1 month well baby check up today. She weighs 7lbs. 14 ounces and is 21 3/4 in. long. I asked what percentile she is at and the pediatrician said that it's not very accurate until two months but she said Maddie is in the 50 percentile. Maddison has had a diaper rash for 3 1/2 wks. Its going back and forth from better to worse but the Dr. said to just keep doing what I am doing and soon it will get better and I hope so. I feel like that's all I do is change diapers all day long. She also got her first shot. The nurse warned me that she is going to scream and she did! Right when the nurse stuck the needle in her thigh Maddison's eyes got really big then she screamed like someone was trying to kill her and then gave the saddest cry I have ever heard.