There are some things that are worth fighting for and some things that are just not worth fighting for. If it is important enough to fight for then as long as you don't quit when the going gets tough then you will succeed. If it doesn't matter in the "big picture" for your future then you need to walk away to save your time and energy for what really matters. Fighting an uphill battle is hard enough without being held up or knocked down by unnecessary battles along the way. Lighten your load by letting go of things from your past that are weighing heavy on your mind.