One day period? Pregnant with iud?

Okay so, about two weeks before my period was supposed to start I started having some early pregnancy symptoms...which of course are all just pms symptoms as well. I was a little worried because my symptoms usual start a few days before my period, not two whole weeks before. My period was scheduled to start yesterday and it did or at least I thought it did. I had some bleeding in the morning and early afternoon yesterday, but ever since then, nothing! I've had spotting before and this is definitely not that. I have been trying to wait it out today to see if it would start back up, but there's nothing. I don't feel like I'm on my period either. I am very tired today though and sorry about the tmi, but I have been so constipated since the symptoms first started a couple of weeks ago. I do have an iud, so I am highly doubtful that I am pregnant, but had anyone else ever experienced this? Any thought would be much appreciated! Thanks!