I've had my thermometer for a while. And I've come down with a cold. Runny nose, sneezing, watery eyes, sore throat....now I think I have a fever but my thermometer takes FOREVER to take my tempature. Like I got this thing suck in my mouth for like 5 minutes waiting( and I can't breath out of my nose) it says 98.2. Then I take it again 10 seconds later and it says 98.5.....do thermometers go bad?