Help pls

Favour

So i was suppose to see my period today 23rd but instead i got a period like on the 20th and it was watery and thin and also looking like rusty red nd it just came for a day nd half followed by mild cramping .. the blood stopped by the half day but since then am either having headache or mild pelvin pain plus my breast feels fuller than before, I haven’t taken a pregnancy test yet cos i dont know what is happening,,, plsss ur suggestion would be needed