Well it depends a bit on what Black does if you are looking for a name for this, it could be a Scotch Game or Four Knights Defense. In the Scotch d4 is played before Nc3 and in the Four Knight's it is usually premature to play d4 so early......It sounds like you may be playing a hybrid between these two systems.

It has been said that the opening is over when the rooks are connected on the first rank. In Modern Chess, this is a bit of an oversimplification, but I would say that when one side is done PREPARING his plans, and starts IMPLEMENTING his plan, then the middlegame has started.

Although I disagree with some of his analysis, Eric Schiller has written an excellent book on this subject called "The Big Book of Busts". The best way to combat an unusual opening systyem is usually NOT to try to refute it, just develop normally, making sure you keep your share of the center and above all, keep your development smooth and flexible. Many of the more unsound lines depend on the other side falling into one or two traps, and if you avoid them, youre opponent will have nothing.