AF so soon? I didn't even know that was possible!

Oddly enough I came on here to post almost the exact same thing. My lochia stopped about a week ago and today (baby is 4 weeks old) I have bright red bleeding though it's not very heavy. Can you seriously get AF so soon after birth? How could there have been enough time for anything to even acculmulate in there? I really hope it's not AF, I'm so not ready to deal with her yet. I have an appt with my Dr in 2 days so i will mention it to him and see what he says.