Please, i engaged in unprotected sex a week ago. and just this sunday i engaged in another unprotected sex but took a contraceptive pill, later in the evening i engaged in an unprotected sex and took no pills. and i'm having a yellowish discharge?

Colored vaginal discharge usually means an infection, especially STDs. See a doctor or clinic for in-person evaluation, including testing for gonorrhea and chlamydia. Good luck.

I can’t answer your question. I do think that you should consult with OB-GYN. More importantly, I think that you should exercise a little more caution, and use protection.