There are several ways to find out if you are in fact pregnant:
you can test your urine at home with a home pregnancy test
you can have a blood test ordered by your doctor
you can have your urine tested by your doctor
your doctor can do an internal examination.
A blood test will give you a reliable result, even at the earliest stage of pregnancy (can detect a pregnancy earlier than a urine test at about 7-12 days from possible conception). Your doctor will order the blood test that will check for the pregnancy hormone, human chorionic gonadotrophin (hCG), in your blood. You can have this test done as soon as you have missed your period.