I had Sex with my husband 3 days before my period was due, he came in me... my period came late or what I thought was my period. It was lighter than usual and now there's no blood at all.. I heard of implantation bleeding but it was heavier than that. What could this mean?

I could mean you are pregnant, you may have to wait till next month and see if you have a regular period and if not, take a HPT.

It could be an infection of some sort. It could mean you are merely going to be late on your period, or miss this one, that is not uncommon either.