Had sex at 3/26 withdrawal method. were sure he peed beforehand & didn't ejaculate inside me. i feel lightheaded and nauseous its a day b4 my period?

Just watch...: I'm proud of your intent to avoid pregnancy. Despite such carefulness, withdrawal technique still carried its high rate of failure. So, just watch and observe potential pregnancy-related symptoms and do pregnancy test 2-3 weeks after missing the expected period. In the future, better contraceptive techniques may be used, but of course, each comes with its own risks - so nothing is free. See doc...