Drank alcohol, took planb and a week later heavy bleeding,had sex a week ago and period is late 6 days, 2 negative tests, pregnant?

No.: Pregnancy tests are very accurate so repeating the test will not change the result. Plan B is progesterone and caused you to menstruate thus "resetting" your cycle. You should expect a period within 3-4 weeks from when your menstration last ended. If you don't get a period in 5-6 weeks from last menstrual day then recheck pregnancy test. If still negative consult with your primary doc or OBGYN