What can be done about wanting to change things in the present that you can't?
There is only now, the present moment. There are thoughts about the past, fantasies about the future that are arising in the present moment.

What must be done is to become aware when such a thought do arise, and to observe that thought, objectively. Without investigation or analysis, without reacting, by simply turning, holding and sustaining your attention to what has just appeared, just at time of its duration.

You will realize that when you do this, the thought will simply disappear, it will vanish.

Ultimately it is only a thought, nothing more. The problem is that we create more out of it. The desire to control what is out there will only lead to your own misery. Let it go, give it up.

Have you ever heard about satipatthana / vipassana ?

This should help you, friend.
http://en.dhammadana.org/vipassana/what_is_it.htm