I missed my period but tests come back negative. was 7 weeks along when they came back positive with 1st child. could it be the same situation?

Trust the test: Home pregnancy tests are very accurate. They are the same tests used in a doctors 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. See doc for irregular periods and birth control.