Contraceptive Implant - Spotting

I had an implant inserted in my arm about 2 weeks ago when I was on the 5th day on my period. When my period completely finished 2 days after, I had sex with my partner because the nurse said that the implant will start working straight away. Today I noticed brown watery discharge coming out. Is that normal? Please say if any of you have had a similar experience as I am getting worried that the implant didn't work. Thanks girls ❤️