Brown discharge after coming off mini pill

So I stopped taking the mini pill on the 2ndish (not 100% sure about the date but it was either the end of december or the beginning of january)

My period was due 10 days ago, but taking into account coming off the pill I'm aware that might not be accurate.

I didn't get a breakthrough bleed after stopping the pill. Yesterday I thought my period was starting but it's just been brown spotting & light.

I took a pregnancy test when my original period was due, and a few days later both negative. But they were not 4 weeks from after I stopped taking the pill.

I don't know whether I could be pregnant (we are trying) whether this brown discharge could be the beginning of my period or if it's something else! Anyone have any experience