Nexplanon problems..

Cl

I switched over from the pill to nexplanon in March of 2016. My doctor said I should wait 6-12 months for it to fully kick in, meaning back to regular periods(if any). Well I’ve been getting my period every other week and sometimes for an entire month since I’ve got it inserted. I haven’t had any other symptoms besides this irregular bleeding all the time and mostly it is just spotting but it’s still affecting my sex life tremendously. Has anyone else had this problem and maybe some advice? HELP