In need help

Rebecca • Mommy of a perfect son 👦 Pregnant with baby #2 👶🏻
So, I've been TTC for about a month now, I'm experiencing really painful lower back pains, extreme cramping, and sometime nauseous.. I'm unsure what is going on. I got my IUD out March 12th, then got my first period March 15, last 5 days (that is usually the time I get my AF each month. Even with the IUD). I got my AF April 2-6... I've been fertile since April 13th. 
Does anyone know what is happening?!