Do I Need To Take An Emergency Contraceptive If I M Already On Giane 35 For Irregular Periods, And Will Chirocyst Affect Its Effectiveness?

Actually, I ve been taking a contraceptive pill name Giane 35 for irregular period. I had unprotected sex yesterday. Now I m thinking of taking an emergency contraceptive pill name I- pill. Do I need to take it? Also I m taking Chiro cyst regularly. Will it block the effectiveness of Giane 35?