Hello, Emergency contraceptive pill (Next choice) is very much effective in prevention of unwanted pregnancy. Though it gives 95% protection if it is taken within first 24 hrs. Here, chance of pregnancy is less, but you should undergo one blood test for beta-HCG to rule out implantation bleeding. Following taking emergency pill, withdrawal bleeding is quite common & normal phenomena. But continuous spotting or light period for 2 weeks is due to hormonal imbalance/ stress if you get negative blood test. Your upcoming period may be hampered due to effect of the pill. You may consult with your gynecologist if it continues after your period over. Some investigation like USG pelvis, hormonal assay etc may be required to rule out underlying pathology. Avoid stress, take healthy diet with iron supplements, eat more vegetables/fruits and drink more water, control body wt and take proper sleep. Practice safe sex in future. Be well.