Right now, the health industry treats "depression" like it's all one thing, which is about as useful as treating "fever" that way. Lots of different things can cause depression, which is why the same solution doesn't work for everyone. Thus people often have to try multiple therapies before finding what works for them (if anything does). It's a gamble.
One of the things that can definitely fuck up your mood and clarity is a crummy diet. If you eat junk you will feel bad. That means if you feel like crap in a society with generally awful eating habits, diet is a good first thing to check when you don't feel right. If your diet is already healthy, move on to other possible causes. If not, consider adding more mood-boosting foods and cutting down or eliminating junk. Depression often has multiple causes, so sometimes you'll find that one solution is not enough but combining several will work. In this case, diet is very often one of the contributing factors, another good reason to check it.
Another aspect is that self-care in general improves mental health, and food in particular. Try pampering yourself with healthy foods to see if you can set those as comfort foods. If you don't have the energy to do that, but you do have people asking how they can help, ask them to bring you mood-boosting foods.