Pregnant?

I'm on Nexplanon. I got it inserted in June and it's been working well for me! However, I am slightly worried that I am pregnant. My only side effect has been white discharge but I have to actually dig inside my vagina to get it like it doesn't stain my underwear or anything. Other than that, nothing else. My boyfriend has finished inside before, but not often. He always pulls out. Should I get a pregnancy test or am I just overthinking this?