I bought one today and DS seems to hate it. I don't think he likes his legs being apart so much. He's going to be five months on Aug 8, so my question is, should I get the insert and use it like a sling for a while or just keep using it as is until he gets used to it. Until now we were using a Balboa Baby sling that I loved, but he's almost 15pounds and it's starting to do a number on my back. TIA!!