Joey- Is that all you changed was tail blades? Did you do something else at the same time to possibly cause it? When the tail blades spin counterclockwise, the leading edge shoulsd face up and the trailing edge down, so it sounds like you got them on right. Double check the rotation is c.c. when you rotate the main blades clockwise. Other things to check; direction of the gyro (did you reverse it on the gyro itself or maybe in the TX settings? Is the tail servo working properly? Are you main blades turning the right way when you apply throttle? Is the belt tension tight enough?

See what you find and let us know.

Jim