Hi its_maerry,
You should definitely take a home pregnancy test. You are well beyond the point of early testing and will certainly show a result.
Have your periods, up to this point, always been regular? You should call your doctor and schedule an appointment and discuss your concerns as soon as possible. You sound very worried.
Did you use protection during sex? If not, you may want to discuss changing your method of birth control when you visit your doctor. You may want to look into an IUD or implant/patch that reduces the chances of your having unprotected sex.
Take care and let us know what you decide to do,
Admin