I WAS 4 DAYS LATE ON MY PERIOD AND ON

I WAS 4 DAYS LATE ON MY PERIOD AND ON THE FIFTH DAY I HAD SEVERE CRAMPS AND A EXTREMELY LARGE CLOT FELL OUT. NOW MY STOMACH AND BREASTS ARE SORE TO THE TOUCH AND I FEEL LIKE I AM HAVING PERIOD SYMPTOMS AFTER THE FACT. I AM REALLY TIRED, MOODY AND HEADACHES. COULD THIS BE PREGNANCY, MISCARRIAGE OR SOMETHING ELSE?