What Does Light Pink Discharge After Having Sex While On Implanon Suggest?

I have had implanon for about 8 months now. I ve recentely been having sex without a condom, he doesn t ejaculate inside of me. I have had sore nipples for about a week and tonight discovered a light pinkish discharge upon going to the bathroom. Should I be concerned about pregnancy? I haven t gotten a period since the implant was inserted.