Hello dear I understand your concern You are on the nexplon implant and it is 99% effective in preventing the pregnancy. Symptoms of the pregnancy is variable. Most common symptoms is the missed period. Other variable symptoms of the pregnancy are: fatigue, dizziness, sore breast, enlargement of nipple and areola, darkening of areola, nausea, white vaginal discharge, implantation bleeding with slight cramp. You can confirm the pregnancy earliest by the blood HCG test, just 10 days after the unprotected sex. I think chance of the pregnancy is less You can also go for urinary pregnancy test when your period will delay by the 8-10 days Avoid stress, take healthy diet, drink plenty of water, maintain proper pelvic hygiene, and do regular exercise Hope this may help you Contact further if follow up needed Brest regards Dr. Sagar