Took ipill after sex, some vaginal bleeding, pain in lower abdomen and legs. What is it ?

hello ma am !! actualy i had ipill on 23rd september and aftr having the medicine i again had sex after 6 hours... next day on 24th september i again had i pill nd after 9 hours i again had sex... on 25th mrning i mean next day i had some vaginal bleeding and it continued for 4 days.... today mrning i mean on 29th september blood flow suddenly increased and i am having pain in my lower abdomen and legs... if these are periods then itz 20 days early... i hav my date of periods on 17th october... Doctor plzzzz help me out ??? is this something serious... please help me out ...