The only time you could have conceived would have been in the two days prior to the IUD insertion and it is highly unlikely due to your exclusively breast-feeding at the time of insertion.
The simple pregnancy
test should answer your question. As to whether or not the symptoms you are experiencing I do a pregnancy fatigue
or the IUD I would recommend pregnancy test as a first step. Next we need to consider which type of IUD was placed. If it was the Mirena or Skyla, it is possibly causing some of the systemic symptoms that you described. If it was a copper or inert IUD then the symptoms you describe are not related. please make sure that you're getting enough iron, enough rest, and continue to take your prenatal vitamins
. If your symptoms persist, you aren't pregnant. and you have a progesterone
IUD you may need to consider alternative contraception