Late and negative...?

So I am currently 8.5 months pp. I got my first period in feb being 7.5 months pp. I was ebf but my son weaned this month.

I fully expect to get a period but I am now 4 days late. I had brown discharge two days before and up until a day late. I took a pregnancy test two days before my missed period and two days after my late period- both negative. Is there still any chance I am pregnant? Or is it most likely just my body trying to get back in sync? I’ve had slight cramping so I though for sure I’d have it by now but nothing and I got super nauseous just a little while ago but that could be completely unrelated and just something I ate as now I feel fine....

Please let me know what you think!