Long period/ovulation

So I went off my birth control at the beginning of December. I had a normal period for 4 days and then from Jan 2 to Jan 15 I had another period. At first it was normal but then after the first 4 days it turned to old/brown spotting.

My app says I wouldve ovulated right after that but I’m fairly certain if I did it would’ve been the following Saturday.

I haven’t started a new period yet and the app says I’m 3 days late. pregnancy tests are negative.

Has anyone else had this happen?