If this is your first O/U then it's going to take a little time to become accustomed to it, if not then you may have bought the wrong model. Different models have different forearm configurations. Holding the gun mounted isn't going to tell anyone else if it fits or not, only if you have it correctly mounted, this time. It's what the shooter see's when looking down the gun. Also if you don't have a consistent mount an O/U is going to magnify any issues you may have, they are not the best beginners guns.
Also the difference between a field gun and a target gun is enormous and will either be really good for you or really bad. A field gun is going to recoil differently than a true target gun and they both feel different. I don't know which one you may have...