I was supposed to start period on the 17yh but started on 15th so I thought. I usually have heavy bleeding for 3 days then it trickles down. I only bled for less than a day and not a lot. So weird and my cycles are like clock work... Could it be implantation?!? I didn't even know I was bleeding until j went to pee! Which is even weirder because I always have terrible cramps !