Had a bit of pain today...

...in my entire general area, like different than I've ever felt before. Wasn't like cramps or even gas cramps. AF isn't due til Friday and I'm nothing if not predictable there. Been TTC for 7 months. Only have 1 tube due to ectopic back in December of 2015. it was just right there where my uterus is and radiated downward and was pretty constant for about 4 hours or so and hasn't been back since. Any ideas? Could it be implantation pain? I'm literally clueless so any insight would be amazing! Thanks ladies!