I stood my 8 month old up in his pack n play like a week ago and now it’s all he wants to do, he will not sit on his butt and if I try to get him to sit on his butt he will cry and straighten out his legs until I stand him up. I can’t leave him standing all the time, but nothing will get him to sit. I tried leaving him until he got tired and sat down but he just ended up falling over and freaking out until I stood him up again. Idk what to do, anyone been through this?