How can you have a missed period breast leakage but still no positive pregnancy test?

It is possible to still have your periods after getting pregnant, although it's not common. Two weeks after you become pregnant, there is some implantation bleeding as the egg burrows into the wall...

nope but the only blood that will be available is the spotting called the implation on the utures

Yes because if when you had sex was close to your period then the pregnancy wouldn't 'register' until your next one. I would suggest reading some of the other questions related to this subject for...

A week after

Yes, some women actually do have their periods during the first few months of pregnancy. Usually, however, these cycles are lighter and shorter than normal.