Why do i get a positive hpt and a negative blood test for pregnancy and ive missed my period this week but i had some breakthrough bleeding for 4 days from last saturday before my period was due?

False positive: If you had a positive home pregnancy test but a negative blood test soon after, it could have been a false positive home test. If the blood test was a while later, it is also possible that you had a very early pregnancy loss.The 4 days of bleeding could just be an early period ( some normal variation from cycle to cycle) or could have been the pregnancy loss. There may be no way to tell.