eegk feel like my body is trying to start my period but I'm on the bc shot and never get periods on it weirdly spotted…

eegk feel like my body is trying to start my period but I'm on the bc shot and never get periods on it weirdly spotted last week never got my first postpartum period sense I got my shot at 6 weeks pp but I'm cramping slightly on my right side can feel it in my lower back right side feels like when your early on in pregnancy and get all those achy period feelings (deff not pregnant though)