I've Had Nexplanon Implant For, I Believe, A Year And

I've had Nexplanon implant for, I believe, a year and three months now. Yesterday afternoon I started getting very small cramps and a faint brown discharge after using the restroom. Today, it was darker and once more, after I used the bathroom. I still have cramps, but I am unsure what they are. I am afraid, and I don't know if this is normal or not.