hi, im 27 years old, and am a healthy person, i have had an iud for around two years now, my periods are irregular, but generally pretty reliable, i get them about a month apart some times a little ealier and sometimes a little later, but generally with in days of when its supposed to happen, how ever, its been 37 days since my last period, right when i was due to get my period i had all the usual signs that it was about to arrive, but, it just hasnt, some times when i go toilet, when i wipe there is a small amount of blood on the paper, but not much, no spotting in my panties, or sign of bleeding in the bowl.. how long should i wait before i see a doctor, is it possible im pregnant?