It’s important to know that if you have an implant like the Nexplanon, you are already protected from getting pregnant. In fact, it is one of the most effective methods of contraception: only about 1% of people will get pregnant if they have the implant. So you do NOT need to take emergency contraception like Aftera if you have the implant. Since you already took it, some side effects you might have experienced include nausea, fatigue (feeling tired), vaginal bleeding, abdominal pain, and breast soreness. If any of those symptoms have continued or gotten worse since you took the Aftera, please make an appointment to see a doctor.
One more thing: if your partner didn’t use a condom, make sure you are aware of whether they’ve been tested for STIs. Not using condoms puts you at higher risk of transmitting STIs, so it’s a good idea to get tested in about three months if you aren’t sure of your partner’s medical history (it takes most infections a few months to establish themselves in your body, which is why it’s not necessary to get tested right away).