What Causes Nausea,dizziness And Sore Breasts In Spite Of Using Mirena?

Hi..for the past 2 wks I been having nausea and dizziness and now for the past wk my breasts have also been feeling sore those sound like symptoms of pregnancy but I have the mirena, could it be pregnancy or just symptoms of the mirena? I have never had symptoms with this iud and it's almost been 5yrs that I've had it....