Can weaning mess up your cycle?

My husband and I recently decided to try for baby #2. I happen to be about a week away from completely weaning our 13 month old boy. I’ve been told that can affect your hormones and mood, but I’m unsure if it can make your period irregular? I ask because my period was due 3 days ago. I’ve been on a regular 28 day cycle for months now, right as rain. But my pregnancy test said negative. Is it possible I ovulated later than I thought and I’m pregnant? Or could the fact that I’m weaning delayed my period?