Does Pregnancy Cause Heavy Abdomen Pain Or Is It Normal During Periods ?

i started noticing slight abdominal pain and it went away and i also started to notice a light brown colored blood but only when i wiped, i figured i might possibly be prego but then i woke up this morning with really bad abdominal pain to the point where i kept tossing and turning and the blood became alot heavier and darker red with a dark brown almost black color mixed in, and a clot what does this mean