IM CONFUSED

Emily
I had my nexplanon put in on the 3rd of April and it was my 4th period day, do you think I would be fine to have sex and let him ejaculate in me tomorrow even though it's during my fertile week or should I wait a bit longer, it's been nearly two weeks!!?? I'm also worried cause I haven't had any side effects and it makes me think that it's not working?