I have defintely had periods of unexplained very low motivation and lethargy. I've done the "listen to music and get really drunk alone" thing a few times. It did seem to help, though I didn't do it with that intent. It kind of slapped me in the face with a "you are pathetic, get over it" message that really sunk in. It has been a few years since I have done that.
I also started exercising (weightlifting) about 2 years ago, which is something I never did before. I have tried other exercising (biking, running, swimming, etc.) but none of it ever stuck. Weightlifting did for some reason. Barbells, not machines. Squat, bench press, deadlift. Read or watch some videos from Mark Rippetoe "Starting Strength." I can't say I enjoy doing it, but for some reason I have kept at it and I do like the effect on my body. I'm 55 and have the best muscle tone I've ever had in my life.
I also take a regular multivitamin every day, along with moderate additional C, D, and Zinc. I don't get headaches anymore and I hardly ever even get a cold. I don't eat fast food or drink soda, I eat mostly chicken, steak, and salad and drink water, coffee, or tea.