Period late

My period is almost a week late, I was taking the contraceptive pill last month but stopped taking it 4 weeks ago as I was constantly on my period.

I was like clockwork before this, I've taken the pill before and when I stopped it didn't make me late.

I've been logging on this app and it says it's late. I don't know how reliable it is.

Starting to worry! Do you think it could just be the pill?