Of what could have beens...

With each passing day, I can't but stop and let these thoughts flood my mind. All the what could have beens. Is there something I could have done before, that would have made my present any different from how it is now? The helplessness of my situation, am I wrong to let my mind drift away from my present to my past or even worse my current uncertain relationship? What I have brought upon myself is mostly my fault, however much I'd like to find someone else who can take the blame.
Why do your future and your present ask you to let go of your past? Why don't they understand, I am what I am because of it, for better or for worse.