I'm not sure I quite understand this. It has happened every single time I bought a coin. Whether it's BTC, VTC, XPY, BC, DRK or even LTC. It doesn't matter what I buy it shits itself as soon as my buy order goes through. As soon as I get tired and sell it starts going up. 
You are a gifted individual. You should run a hedge fund making the most out of this "talent". Just sell when you want to buy and buy when you feel it's necessary to sell.
Stop complaining and get back to making $$. Your battery of luck seems to be installed incorrectly, change the poles before it got damaged or your cash will burn a hole in your pocket.
