About 4 months ago I found an adult female bed bug on me. Just one. I was on my bed so I searched all around my mattress, box spring, floor anywhere I could think of in the vicinity and found nothing. I had no bites on me. No signs. Just tonight, about four months later, I saw another one. I did the same thing. I searched harder. Still, I find nothing. No signs of excrement, larvae, nothing at all but these two mysterious adults. What does this mean? What should I do?