2008 Chevy Silverado Engine working too hard

Hello fellows. We purchased a new Silverado. After 2 months the engine is racing as we push down on the gas yet we are going slow! We have contacted the dealer(we aren't at all happy, obviously) and they have to take a look at it. Is there any way to determine if we did something wrong to cause this problem(being featherweight on the gas, babying the truck)or does this sound like a possible lemon. We will find out, but have you ever heard of such a young truck having engine trouble so soon? I am insisting that they tow it to the dealer when I call them tommorrow, we could barely get up to 40mph!