I Had The Implanton About A Year Now But About

I had the implanton about a year now but about a month ago I noticed that is was bent not broken even my obygn just kinda felt it and said it was okay. Lately I have had bad cramps bad headaches even feeling extremely weak and shakie. I've taken a pregnancy test but neg. Is it possbile to get a false reading because of the birth control? And are these symptoms alarming?
Thank you