Mirena crash or pregnancy?

Kate
I had my Mirena IUD removed on September 18th, and had AF immediately afterwards (it actually started the morning of my afternoon removal appointment). AF was due on the 16th of October, but has yet to show--it is now the 22nd. I have been cramping for the last two weeks off and on, PMS like mood swings, and sore nipples. I fear it is just a hormone withdrawal from the IUD, and don't want to get my hopes up too much--it seems unlikely I could have conceived so quickly. Has anyone else had Mirena experiences they could share? I will take a test this weekend, but I am curious what experiences others have had with Mirena. I feel crazy!