So 1 month after intercourse i got negative in pregnancy blood test, it accurate? so the bloateness, loss of appetite, and vomiting when i wake up, thightening of stomach is not pregnancy anymore? maybe some medical issues?

Tests are accurate: Pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, or medications. A home urine test gives a reliable result by 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If still worried, can test one more time with a home urine test, if no period comes after another week.