Implantation day!!

Hey ladies so another app informed me that today is "IMPLANTATION DAY" if me and my husband were successful during my fertile window. So i figured it would be like any other day and i wouldnt feel anything but since i woke up this morning ive been cramping and my stomach feels soo sore it even feels uncomfortable to take deep that weird or what? I know its not just in my head cause im feel pain. Should i be worried or is this normal? #freakingout