J.A.
Hi K.--
I could have written your post-- I'm having mine removed this week! Since the hormones in the Mirena only work on the lining of your uterus (most women still ovulate when they have the Mirena in), return to fertility should be quick. Since most women don't get periods on the Mirena, one recommendation is to wait at least one cycle/period after having the Mirena removed to re-thicken the uterine lining. This will also help with more accurate dating of the pregnancy.
Good luck!