Another Mirena IUD question

I got my Mirena in December of 2015 and I had regular but lighter periods since then but this month my period is late by 19 days. I looked online and many ladies who miss their periods with the Mirena say they have cramps but no period. I have no cramps and no period and I also feel bigger. Could I be pregnant? I would check with a doctor but I have no health insurance right now. Should I just buy some tests or wait it out?