Car likes to keep going...

[Manarius]

When I'm out the highway, whenever I get on the brakes to get off at an exit, my car sort of "lets go." As I mean to say, it tries to keep going when I put on the brakes. It feels like after I tap the brakes, either the engine or tranny lets go and the car feels like it's broken loose of...something. Does anyone else have this sort of thing? I know our cars like to keep going once they get going, but this sensation I get is a little weird.