Suggest Remedy For Delay In Periods

Hi I am a 21 year old female and took myself of the contraceptive pill after 4 years in December. I have not had a period since I came off the pill. Recently I had unprotected intercourse and did not use the morning after pill as I could afford to get it. I am just hoping I am not pregnant, it is too early to do a pregnancy test. I always had irregular periods before I started taking the pill. Please help put my mind at ease?