What Causes Heavy Bleeding And Blood Clots During Menstruation?

hi i was a week late on my period and started having pregnancy symptoms morning sickness fatigued then bout a week later i started having cramps and when went to bathroom i found some blood after that the next day i had what seemed like my period which was fairly heavy a day later in the toilet i passed a fairly large blood clot then passed a few smaller blood clots days after then on monday the bleeding subsided yet when ever i go to the toilet after monday when i wipe myself i still get a fair amount of a deep red blood appear on the tissue and really confused on what is happening