Had d&c first cycle came exactly 4 weeks later now 2 cycle is three days late feeling nauseaus yet pg test shows neg?

May have tested too. Soon. Home pregnancy tests start turning positive 7-10 days after a missed period. You may repeat the test in a week or see your doctor for a more sensitive blood test.
Do another one. If no period in 2 more weeks, do another pregnancy test. If still negative, wait until the next period is due. If no period again and pregnancy test is still negative, see your doc. You may need to have your period induced.