Periods Nexplanon and Zoloft

So im on day 15 of my period with cramps and all the pms. I’ve always had a semi irregular period that I can remember. But since I started new medicine in November I’ve had a few periods that feel like they never end. Every month around the same day I get my period. But either it comes back after a few days of it being over or it lasts this long with maybe just maybe a day or two break in between. My physiatrist says it has nothing to do with the meds I’m on but google (I know) has told me anti depressants can cause irregular periods even more. Idk if I should switch my birth control and see if that helps or what I should do. My life is literally 2 weeks of period a few days of nothing a few days of spotting and BAM Period again. Non stop.