A faint line on a home pregnancy test would be a good indication that implantation had occurred - unless you were recently given an injection that contained hCG...
It is usually recommended to wait until the day your period is due mostly because not all early pregnancies continue, but also because some women will still get negatives even the day before, even though they are pregnant.
Looking forward to your update!
Rachel Inbar
www.FertilityStories.com