Feeling sick vomiting nausea. 24 days after sex both blood and urine negative. What's wrong with me? Am I pregnant?

Trust the test. Home pregnancy tests are very accurate. They are the same tests used in a doctor's office. They can detect a pregnancy 7-10 days after conception. The best time to take one is when you miss your period. If you doubt the result you can repeat it in 1-2 days. If you were pregnant the hormone level would rise enough for detection.