Slicing my Irons

[KGab11]

I recently bought a new set of Callaway X-20 irons. I hit them at the range a few times and was hitting them long and straight. Since, I have played two rounds and I cannot hit my irons straight, or long. I hit my driver straight and average around 300, and I never had this problem with my old irons. Yesterday I scored an 80 (Par 71) but could not hit my irons straight from 145 and out. I don't understand how I could go from blistering my irons at the range longer and straighter than I've ever hit to hitting them so bad that I want to sell them. I'm not going to sell them, but when you are out there hitting long and perfect drives and putting good but can't hit an approach shot, it get's very frustrating. Someone please help me