Emergency contraception (i-pill) should not be used very often like in your case. Frequent usage of the emergency contraception can disturb the cycle's regularity completely. Vaginal bleeding after taking the i-pill is a normal event. A white discharge and burning sensation from the vagina is not normal and is probably due to a vaginal infection. Not all vaginal infections are considered to be sexually transmitted diseases. The most common vaginal infections like candidiasis (vaginal soor) and bacterial vaginosis are not sexually transmitted.

Cervical cancer often has no symptoms in its early stages. Vaginal bleeding right after sex (contact bleeding) could indicate cervical cancer but that possibility has to be confirmed with certain tests. Each sexually active woman should perform a Pap-test once a year.

You may consult your gynecologist about this.