I really hope for your sake that you are not pregnant, although it is certainly a possibility. I'm one of the very unlucky few who fell pregnant right after removal. I also then had a very early miscarriage only 5 days after a positive pregnancy test. I suggest you get a test done by the doctor or at a family planning clinic. Or leave it another week or so then if you still have not had a period you could do another home test. I was quite late getting my next period too. So late in fact that my doctor insisted on doing another pregnancy test just to make sure. And I must admit that until I stopped this most recent period I still had so many pregnancy symptoms. I believe that mirena is a very nasty little thing which does terrible things to us poor, unsuspecting, trusting women; not only while it is inside us, but for much longer.
Get a proper test done if you are really concerned, and please let us know how you get on. Take care!