You may need to start going through a grief process before you begin to feel productive and closer to thinking positively about life. The grief process, as described by Dr. Elisabeth Kubler-Ross, involves 5 stages. Each of these stages should be considered a temporary stage, not a permanent one, with the exception of the last stage. Those stages are:
This stage is where we think that this isn't real and all will go back to the way things were if we just give another person a little time, they will come around. This stage helps us begin to survive the loss of something.
This stage is where many of our emotions may come out after the initial shock of an event has happened. Letting the emotions of hurt, fear or frustration out in a healthy way can make room for being productive in the near future. Addressing the anger and not ignoring it, can help this stage be temporary, not permanent.
This is the stage where we think if we did one thing different, like promised never to use those words again or devote our life to helping others that this will all go away. It's the "What if's ..." stage.
In this stage the loss becomes deeper. We have worked through some anger and what if's and nothing is changing, so we need to begin to address some reality. Having a good support system and plenty of people communicating with you as your sadness comes to the surface is key. It is OK to be sad. Again, we want this to be temporary though, not permanent. Be sure not to isolate yourself. You most likely need to be with people. As you talk about your feelings and embrace them, you can begin to move to the last stage. If emotions are not your thing, being able to talk to a trusted individual at least regarding the facts of what is happening and have that person validate you in some way would be helpful.
Here we are getting to the place where we have to reorganize our life and begin to accept the reality of our future. A future without whatever or whoever you lost. This gets more manageable with time and taking advantage of the many resources available to you. We want this stage to be permanent but know that you may bounce between the other stages, out of order, and multiple times before Acceptance shows itself.
In addition to going through this grief process you can also break down what you are going through into smaller parts so it feels less overwhelming. For example, if going through a divorce or loss of someone close to you, there is a lot to do. Make a list with a trusted individual of what has to be done. Revise that list and cross off things that get done for a sense of accomplishment. Once the news is out, your support network may approach you and ask if they can help. Take them up on it. It is wonderful to help someone in need. In a short amount of time, you may feel less overwhelmed and ready to take a step towards that positive vision of a future life.
If you are still feeling that you are unable to work through things and that life still feels unfair with the same intensity that it did in your recent past, please seek professional help to begin that journey back to a positive vision of life. A great national resource for that help is www.psychologytoday.com.