Is that even possible?

Is there anyway I can get pregnant on the Nexplanon implant. I’m late on my 2nd period since I got the implant (9 days late). I have sex weekly with condom (sometimes it falls off then we just stop having sex. He never has came in me that i know of.) Got implant in July 9th. And waited 2 weeks till I had sex. I’m nervous even though the implant is 99% effective. And i know that periods stop on implant too. I just like to be reassured. I’m spotting still and have been shedding the lining of my uterus it looks like when I pee. Rare spotting though. After sex sometimes I bleed old blood it looks like which scares me. So should I take a pregnancy test and go to the obgyn or should I just stop stressing?🤦🏼‍♀️