Period late but bleed for one day and then it stoped

Hi I'm a 23 year old female my period has always been on and off but i always got it either 2 days late or week early last month on april 10 i got it 10 days late but it lasted  for 4 days and it was light from then on i ve been feeling sick (not throwing up) felt dizzy hungry all the time then i took 2 test and they both said negative --well on the may 14th i was having sex with my boyfriend and i was bleeding so i thought ok my period came on  that whole day and night  and today all day i have not had one drop of blood but am having a sharp pain on the sides of my stomach it would help alot if i can get some type of insight about this thank you so much

xoxo lost and confused