I feel this way at times due to illness , you know, what is the point? look over your diet and try and make sure it is good and maybe add some vitamins. I also found adding some amino acids like taurine can be helpful. Or maybe you might respond to st johns wart or other similar type herbal preparations.
Get some sunlight and exercise and put on some music. Music does so much and can be so healing.
try and get out and find people. My hubby and I are trying to get to the senior center a bit , at least it gets us out of the house. Here you only have to be 50 join . Do they hare recreation centers where you are at? Those can be wonderful, just get out of your apartment and people watch. Hey just sitting on the steps outside your apartment is better than watching games shows all day.