What Are The Side Effects Of Using Emergency Contraceptive Pills?

hi, i had my period 13 feb, had sex on the 23 feb sperm when in i took a morning after pill the next day i bleed the bleedin stop then i had sex 28 feb the bleeding cont for 10 more days. havent seen my period for a mth. then on 8th april i had sex wit my bf sperm when in then i see my period the next day for 6dys now am getting som pain in my belly.