Hi, are you taking lessons at the moment? If not then that's always the best place to start to get fundamental swing mechanics in place.
It sounds to me as though you are trying to lift the ball off the ground with your swing. All
irons are designed with a loft that will do that for you so your aim is to hit the ball with a descending blow.
To get the feeling for how this should feel, try this when you are next at the range.
Before you hit any balls with a full swing set up with a ball next to your right foot (if you're a right handed player) and with a sand wedge or pitching wedge take a backswing simply by turning your shoulders only until the clubhead is about knee-high and then swing through the ball gently and smoothly.
You should find that the ball pops forwards quite nicely with a very solid impact. By moving the ball backwards in your stance, you've ensured that you'll hit the ball on a downwards path and that your hands will be ahead of the ball. By taking a short swing you'll have also eliminated or minimised any problems with swaying or lifting up with the body.
Now, gradually work upwards to a half swing with the same club, concentrating on the same idea of hitting down on the ball and keeping the movement of the body limited to shoulder turn. Once you're hitting the ball consistently like this then you have some of the fundamentals of iron play in place.
Good luck and above all have fun.
Paul