can you trust nexplanon?

I know this may sound dumb but I am just scared because this is my first time with this. I had sex yesterday and the condom broke when he came so it may be possible that some did get inside of me. But I got the implant in 12 days ago. But my friends scared me and told me I don't know if this thing is working... so now I'm paranoid. I can feel the end of the implant just under my skin and as I go down the other part of it I can't really feel as good toward the hole where it was inserted it's still there just I can't feel the end as good as toward the top. But is this ok? I just really am scared.