Could I be pregnant?

First I want to start by saying I have the Nexplonon Implant this is my second implant. My periods are never regular so a missed period is hard to tell, but about a month ago my boyfriend stopped pulling out, and now my breasts are sore and I’m so hungry all the time, my sex drive has went up a lot, but still no nausea. According to this app my period is late by 5 days, but again I have the implant which is supposedly 99.9% effective. I’m wondering if this is just phantom pregnancy or if I’m actually pregnant. I have yet to take a test yet, but any tips?