Implantation bleeding or early light period?

This is our 2nd cycle ttc. I ovulated around April 2 or 3. My period wasn't supposed to come until Saturday. It's usually pretty regular give or take a day and when it comes I get very heavy bleefing and bad cramps for a day or 2 then very light spotting for another 2 days. Yesterday morning I woke up with a terrible backache and light cramps on and off all day. I was very tired and dizzy and havinf hot flashes. Light to moderate bleeding. Just not my usual menstrual symptoms...what do you ladies think?