Are you taking any meds? If so, google them to make sure depression isn't a side-effect as it is of a lot of meds including antidepressants [really!!], anti-anxiety, and meds for other health conditions.

If that isn't part of your problem, you could use amino acids to regulate your brain chemistry so you feel better. Amino acids are used by the brain to produce the neurotransmitters it needs so you can function. One amino acid I find very helpful so I don't feel like life isn't worth living is DLPA that is used to produce dopamine and epinephrine which is what makes you feel good. 5-htp is also important as it puts serotonin in the brain and gut. A good book on the subject is Heal with Amino Acids by Billie Sahley that goes through what amino acids helps what.

Here's a good brain function quiz that shows the symptoms associated with each neurotransmitter. http://drjolee.com/Brain-Function-Questionnaire.pdf

I also want to just say that I've had bipolar 2 for 48 years, and was on meds for 13 years. I've been using amino acids and the mineral lithium orotate to control it for 9+ years now, and am doing much, much better than when I was on meds. The reason why I'm doing so well is because I'm giving my body the nutrients it needs to function.