Big question

So 5 days again my mirena fell out, out the blue unexpected, I went to the er just to make sure it didn't mess anything. And the doctor wasn't 100 precent sure but he said that it might fell cause I could be pregnant. Of course they did blood and pee test to see if I was. And came back negative. He told me to wait a week or so and try another test. Could this be true?! Has anyone heard of it before?!?