Tracking ovulation

Hey ladies! I’m 3 months PP and haven’t started my cycle yet. I’m not on the mini pill because it effects me in a super negative way, so I’m collecting advice on other options/suggestions on how to avoid getting pregnant before my cycle starts again. (I understand that it’s unlikely to get pregnant before my cycle starts back up, but I know I’ll ovulate before I actually start and there’s no way to tell when that will be.)