I had a late period and when it came it was black blood then stopped for hours and then slowly became red blood that only lasted few days,what does this mean?

I was late by 10 days on my period and thought I was pregnant ,I had no cramping pain but on the 11th day I got out of bed and went to toilet and I had black blood coming from the vagina this lasted around 5 hours then it stopped and there was nothing no blood whatsoever until later that evening and it slowly became a dark red.my stomach was bloated before the bleeding and I ate quite alot and still to this day my stomach is bloated and i eat a lot which is abnormal for me,I have had moments where I have felt sick and simetimes been sick also I seem to be tired more often and sleep more This happened last month. Could I be pregnant or is there something else wrong ?