Three Months Ago I Had The Contraceptive Implanon Put Into

three months ago I had the contraceptive implanon put into my left arm. I had in put in while on my period. Since then I've had brown 'spotting' for weeks then what i think is my period for a few days to a week. After that stops i have nothing for a week if that and then the brown spotting and period comes back. Since having it implanted I have had only about 2 weeks of nothing. I don't know if this is normal or not. At first i though it was just my body getting use to the change in hormones but it wouldn't continue for this long would it? It becoming a big pain because i put it in to avoid becoming pregnant and well it is working because i cant have sex at all. I just want to go back to normal and im at my wits end and considering getting it removed.