At six weeks postpartum your cycle can still be settling back to normal, so bleeding this early is often irregular on its own. The emergency contraceptive pill you took close to that time can also shift your next period's timing, earlier or later than usual. So what you're seeing now could be your body's own return to periods, the pill's effect, or a bit of both.
Next Steps
Track your flow and timing over the next cycle, since the pill can make the following period a bit unpredictable too. Please see your gynaecologist to check your postpartum recovery and discuss contraception that suits you going forward.
Health Tips
See a doctor sooner if the bleeding turns heavy, lasts well beyond a normal period, or comes with pain or fever.