Whatever has happened, it happened.
Now you have a few options,
1) Let it go.
2) Hold it against yourself.
3) Do something about it.
If you truly wanted something, you would either...
1) ...try and never get it, but accept it.
2) ...never try and never forgive yourself.
3) ...do something about it, or else, you don't really want it.
There is only one life, one opportunity, and every month, day, and year counts.
Get what you want before someone else takes it away from you forever.