4 days early 2 1/2 days weird bleeding

this is probably the same everyone asks but, i was not due to start my cycle until the 27th, i started on the 23 that day was dark brown to almost black at times, then by morning it was alot heavier and darker red,then come this morning almost stopped but was like a rusty color to nothing but when i wipe light spotting. what the heck could it be, a very short cycle? (im not complaining) but is this implantation bleeding? i was 4 days early or maybe something that could be more medically wrong?? any ideas??