IUD reaching its end. No AF.

Help! Trying not to get a head of myself. But I've had my mirena for it almost 5 years ( comes out in April). First year, normal monthly period. Last 3 years nothing. 
Then starting about October 2015 my periods started coming back. 
I'm now 22 days late and not sure if I'm messing with myself or if I should just take a test.  
I'm so confused. Makes me feel like the IUD is going to stop working before I can get to a dr.