K.E.
ok 1. yes that can happen the home prego tests test for a hormone level but it it is not big enough to trigger the test then it will keep saying no.
2. If you do not want to spend $$ then wait a week and try again. Be careful as if you are though just incase.
3. Ask the Doctor to run a blood prego test that will show even the smallest trace of the hormone HCG
Good luck!!