Vaheguru Ji Ka Khalsa,
Vaheguru Ji Ki Fateh.
Please reference the following video bhenji.
http://www.ted.com/talks/shawn_achor_the_happy_secret_to_better_work.html
The suggestions at the end of the video are entirely within our Sikh practice, and are encouraged (Baba Iqbal Singh Ji of the Akaal Academy suggests we be thankful during Ardaas rather than ask for things).
Over the course of months (life is a process, not an event), I found the simple practice of writing things I'm grateful for and journaling about a happy experience helped me recognize Vaheguru's blessings in our lives. This is happiness to the point of tears at times. It fluctuates, like many things in life. Yet it leads towards the experience of Chardi Kala.
Also, being thankful while walking and doing Simran is a very spiritual act.
These things, as with any solution, will take time. Think of this troubling time as a test. Continue doing good, positive, healthy, and Naam-focused things. It will improve with time.
Seva also uplifts the spirit, more than many, many, other things. Couple seva with Naam and gratefulness for the seva.
I hope this is helpful!