Help!!

So this is my second month ttc since I got my mirena out on may 12th haven't had my period yet due tomorrow...I've been checking my cervix and cm it seems to be high closed and soft with creamy white cm. Well yesterday and today my breasts mainly my left one feels like it is filling with milk. I haven't breast fed since Jan. The very being that is. I have taken a test this morning bfn. So what's going on?