I am 20 years old.. My Mirena birth control fell out at the end of July 2015, didn't get a period until December 2015, and that was my last period.. Didn't have sex until just this past week, but other than that time the last time was right before my last period.. I was wondering if this is normal??? Also, I have been feeling very nauseas & tired lately since about 5 days after I had sex which was on Monday, May 2nd.. Could I be pregnant??