You may want to go see your doctor to get a blood test for pregnancy. Or continue to take home pregnancy tests - a blood test will tell you for sure though.

If you do go to the doctor for a blood test, ask for a quantitative blood test (a qualitative blood test is pretty much equivalent to a home pregnancy test in terms of detection levels). This test measures the exact amount of pregnancy hormone in your system and can give you a rough estimate on the age of the pregnancy. It also can tell you sooner whether or not you are pregnant that qualitative blood tests and urine tests.