I just think that I need your help.
Sometimes I am overswinging and I just don't know how to control my swing.
If I will be able to fix this, I am sure I am going to improve
in my most of my games, but how?
Set a video camera up behind you when you swing, see exactly how far you are overswinging.
The only way to shorten this is to take some wrist cock out at the top of the back swing and consciously try to swing shorter. You have to think about stopping the back swing much earlier than you normally would.
Its something I have found very hard to take out of my game, in fact it is something I battle with all the time.
Try to make a mental clock in your head start at 2 o'clock and finish at 10 or 11 o'clock you should practice this without hitting a ball. I would use a mirror get used to the fell then try it on the course!