Gastro-intestinal symptoms such as constipation, diarrhea and abdominal cramps are not signs of pregnancy. Constipation can occur during late pregnancy but not during the early pregnancy. Diarrhea and cramps could be signs of an intestinal infection.
Vaginal discharge might be present during pregnancy but first a vaginal infection must be excluded.
Missing the menstrual period is the first serious sign of pregnancy, although not always secure. A home pregnancy test is the best, most efficient way you can check if you are pregnant, or not. Then, you can confirm the test again at a gynecologist's office using a more accurate blood based test, and ultrasound confirmation of the fetus.