Help please i really am not sure whats going on?

well i had my period on the 24th of nov it lasted till the 30th on the 20th of dec. i spotted for the day just when i wiped and a little in my underwear. it was very very light and was just old blood just a little brown not red (sorry tmi) well i am support to get my period on the 24 again and i didnt its now the 26th and no aunt flo. im ually active so im just wondering whats going on i dont have cramps and my are full and tight. any info or opinions would be very helpful