Society likes to say "think positive", and "dont' worry be happy". But..
Positive mindset is not enough, but it is a criteria for success. Planning, and implementing that plan, is also not enough, but its the structure to moving forward. Often we focus on the right methods, but headed in the wrong direction.
You're right, brooding on challenges in our lives is time/effort wasted, but its often through these dark times, we learn the most about ourselves. If you do anything, start writing about who you are now, how you feel about it, and what you are doing in that moment to change it. Keep it in a safe place, and read it a year later. It may not be apparent now, but that document will be a priceless commodity in understanding the mindset within failure, and the a rear view of what you did about it. Good luck brother, keep that hope and lift hard.