I'm almost 6 weeks postpartum. I got my depo shot almost 2 weeks ago. I haven't bled for almost 3…

I'm almost 6 weeks postpartum. I got my depo shot almost 2 weeks ago. I haven't bled for almost 3 weeks, just been having discharge since then. but last night I've started bleeding again? is this normal? it's kind of dark brown on my pad but pink when u wipe.