Menstrual cycle changes do happen when one takes emergency contraceptive pill
like I-pill. The bleeding that you had 2 days after taking the pill most probably was a breakthrough or withdrawal bleeding. You should not worry about that.
The bleeding that started 3 to 4 days back may be your actual periods.
Please relax, it should all settle down and your cycle will be normalized again. Avoid using i-pill quite often. Consider taking a regular contraceptive pill.
All the best.