Why, oh why

Why is my Amazon order now not going to make it in time for Christmas? I ordered everything on November 18th. They sent me an email TODAY that one item was delayed 4 to 6 weeks, but that the rest should arrive before Christmas. I went in and deleted the delayed item, and now the rest of my shipment won't arrive until AFTER Christmas! How does that work! I upgraded my shipping to the fastest possible, but it's still not for sure. I hope it works out though, otherwise I'm kind of screwed for a lot of presents. Grumble, grumble....