Hear me out

Tomorrow will be a week late on my period. The mirena never stopped my periods I always got them on time until this month. Since my period last month I couldn’t feel my string anymore but brushed it off as nothing and it was probably normal. I took a test on day 3 being missed and I couldn’t tell if it was negative or a vvfl. I get paid Friday and going to buy more tests then. I have all kinds of “pregnancy symptoms” and have no feeling of my period coming soon. Tried calling my ob yesterday and today but still no answer and I’ve left voicemails for them to call me back. Has this or something like this ever happened to anyone else? Is it possible for it to move and I not know and get pregnant?