Hi, I Stopped Taking The Pill Approximatley 4 Weeks Ago

Hi, i stopped taking the pill approximatley 4 weeks ago and still have not yet had my period, have taken pregnancy test which came back negative as i knew it would. Every time i have stopped taking the pill in the past i have had my period withen a week or 2. Is it normal for it to take awhile to get it again or is this something i should be worried about