Gratitude is a good way to change your mood. You can improve on that.
1) Write down at least 10 successes you had starting from when you were born up to this present moment.
2) Every morning as you wake up experience each success in your imagination FEELING the excitement of success before you go to the next success starting from the earliest success up to this present moment.
3) Be grateful for each success only after you experienced the excitement of the success. RELIVE each success in your imagination FEELING it.
4) You will find you are on a HIGH when you reach this present moment in your imagination. NOW imagine the future successes you desire as if it is happening in the present moment.
May you have a successful day. You will find now it is easy to use your imagination.
This advice I got from a very successful man who also was down and out at a stage.