Standing up in Crib


My little girl will be 1 on the 21st. She has been sleeping from 7pm to 7am since 4 months old. The past few nights when we try to put her down to sleep she keeps standing up and playing in her crib. Sometimes she starts crying. We try to lay her back down but she gets right back up again! This will go on for at least an hour until she finally goes to sleep. She is also starting to wake up 1-3 times a night doing the same thing. I feel like I have a newborn again! Is anyone going through this or have any tips? Thanks!