If you are two and a half weeks late but took hpt it was negative ovulation test said were ovulating so had unprotected sex that night can be pregnant now?

If you are saying you had unprotected sex one night after an ovulation test said you were ovulating and this was 2.5 weeks ago, it is possible you could be pregnant. However home pregnancy tests are very sensitive these days and should be able to detect a positive pregnancy within a week to 10 days after a missed period. So if your period is 2.5 weeks late, a home pregnancy test should be able to accurately tell you if you are pregnant.