Three days late now I am spoting. Why??

Hi I was expecting my period on the 5th but it didnt come untill yesterday morning.

This is not like me nomral periods these time I do not have an cramps what so ever when normally i suffer very badly with them.

Also I am not bleeding no way near as much as I normally do. I had the smallest amount of blood on the top of the first tampon i put in. Then when i went to change my 2nd tampon there was no blood at all.

I havent changed

My deit,

sleep routine,

I am not on any form of contraception or medication

I do not take drugs

And I am not stressed

I might add that I have been extra tired the past week or so when I am normally full of engery. (even tho I am getting the same amouth of sleep)