Brandi, not sure about the fatigue, but they do clear quite fast- within a day, day and a half once you stop taking them. If you're that concerned, you should stop. And I really don't see how the Mirena was effective, say, last week, but magically stopped now and won't be somewhat effective for another week and a half. Yes, these things can loose effectiveness, but it's not like it turns off immediately. A week or two here or there will not make that much of a difference on something that's meant to last 5 yrs.