Period questions

I usually have my periods 1-2 days late, however my last period came 3 days early and that is very unusual; that never happens to me. I only had really light blood, quite a dark reddish, an I had cramps and a little pain in my abodomen but not like period pains I usually get and I didn't really suffer bad with the bottom of my back and usually I'm in constant pain just before an during my period with my back and stomach; the sporting lasting up to 4-5 days.... Is anything wrong or something goin on? Could it be implantation bleeding or just a normal messed up period? Need help ladies please..