My implant

So I just got my nexplanon implant a week and a half ago and I’m not convinced it’s working. I don’t feel any different and I haven’t had any spotting or anything. I know that’s great but it kinda worries me too. Is it possible that my body is immune to the hormones and just doesn’t work? Is there a way my doctor could test it at my follow up appointment. I don’t think I’m pregnant because I’ve only had sex once with the implant and we used a condom and he pulled out and that was more than 7 days after I got the implant. But there was one day that we were messing around and I gave my boyfriend a blowjob and I could have had precum on my hand. I think I rinsed and dried it off but I can’t remember. But I do remember going to the bathroom to dry myself off downstairs and I’m just afraid that some how precum sperm could have traveled from my hand to the toilet paper to my vaginal area and my new birth control wasn’t supposed to be effective for another day. I’m just freaking out cus I don’t know if this is working or not