Suddenly an irregular cycle, now a week late.

Hi everyone,
I haven't been at this for very long myself, but I'm dealing with the following. I stopped taking the pill after two years, back in mid-October. A few days later, I got my last period. After that, I waited for my first real period. It came 31 days later. I was happy at first because I read it could take months to get back into a regular cycle. But I didn't really have ovulation symptoms. I did calculate them using an app. But now here's the strange part: a few days after my "ovulation," I suddenly started bleeding—pink and brown blood. It lasted for a few days. Now I'm on cycle day 38 and still not on my period. I don't understand what's going on . I took a test yesterday and it was negative. Not in the morning though, but in the afternoon. What do you all think?