I was prone to depressive states (I say depressive states, not depression, because I was never "diagnosed" by a doctor, but there was a stage in my teenage years when I felt tired, exhausted, and because of this I went to the clinic for health tests, almost every doctor I met even for a few minutes recommended to go to the "sadness doctor", but I didn't want to admit at the time that it wasn't a physical issue (although almost all studies showed that I was physically healthier than the average city child), but a psychological one, so I didn't go) - I had months not wanting to do anything, even get out of bed, and it could feel like the whole world was meaningless.
The feeling of meaninglessness was primarily helped by volunteering at an animal shelter (it seems to me that any kind of help to someone else and seeing that you can change or even save someone's life is a huge push towards the realization that after all we are important and our lives have meaning), and from the physical side what helped me the most was a healthy diet and cleansing the physical body - raw food, fasting, etc.
The problem is that when you are at the peak of that depressive state, you don't want to do anything - and especially to take steps to start taking care of yourself. But, I think, if a person gathers the strength to ask for help, then he already has the opportunity to start changing something even with small things.
It's one thing if that depressive state is simply a great physical fatigue - then the most important thing is to give yourself rest. Here you need to be able to take time for yourself. Because even a week away from everyday life and allowing yourself to just sleep normally can make a big difference: from an empty glass we will not fill anything for children, relatives or friends, or at work. So it will be much better for everyone if you take a break and take some time for yourself. Because when you are full, you can share, and when you try to give something, when you feel that there is nothing left, it is not only that you will not be able to fully give "something", but also some subconscious hurt of those to whom you are trying to "give" may remain. And this is harmful to both you and that "recipient".
If I fell into such states in the last few years, it helped to remember the insight of an acquaintance that Depression is the pleasure of our lower self. Notice that you enjoy that state in a masochistic way. If it weren't for pleasure, we wouldn't be in that state - and in fact, at least for me, it was really a kind of pleasure, such a safe state where I can be a victim, care about nothing and feel sorry for myself. When I understood this, the victim immediately disappeared - I realized that this is in a sense a choice (although it is not clear that I consciously decided "now I want to be depressed"). And if I get into that state and I feel like I want to stay in that state, I don't feel sorry for myself anymore, I don't try to fight or anything. I just let it be - if I'm already enjoying it, so I let myself fully enjoy it. And all the suffering from those states is gone and it goes away very quickly... Another very, very important fact: it is very often simply an imbalance of physical vitamins/minerals/hormones. Therefore, if you fall into such states, start with MAGNESIUM, Vit D and Probiotics. Scientists have recently shown that magnesium is more effective in the fight against depression than antidepressants. And in the bodies of almost all suicidees or suicide attempters, it is significantly lacking. I like magnesium salt (Epsom salt) baths the most - I would even say I'm addicted in a way, because I tried it and now the whole house is full of salt, so that if I go to the bath, I can add salt :). Also, natural, ceremonial, high-quality cocoa is also a wonderful source of magnesium.
And leave medications as the very last, secondary option and in no way become addicted - if antidepressants seem necessary at some stage of life - OK. But from the day you start taking them, don't look at them as a rescue, but as a temporary band-aid that needs to be removed as soon as possible - and start using that medication to get your physical health and life in order so that you can get off the medication as soon as possible. Depression is not really a "deficiency of antidepressants in the body". And many, many people become very dependent on antidepressants. Over the past few years, I have met many people who are taking antidepressants. From a spiritual point of view, it seems to me that those drugs automatically block everything that comes - emotions, inner "demons" etc. , a giant cluster of dark energies. I happened to be around someone who was gradually weaning off antidepressants after taking them for many years. It seemed that all the emotions, all the inner darkness rushed to the top in such huge bursts. When there are people in spiritual events who do not take antidepressants for a short time, they always have very, very strong complex processes, because there are so many emotions and difficulties accumulated and not felt... I even, in a certain sense, look at antidepressants as some kind of drug, where you need care and help to "get off" from them and the period of absitence is very unpleasant...
By the way, if a feeling of guilt starts to arise that "oh, I'm such a loser, that I'm depressed here now, why can't I be like normal people, etc." remember that every time you feel heavy energies and finally get out of them, you are helping not only yourself, you are helping the whole earth and humanity - you are transforming some of the heavy energy living on earth into light. Part of the soul mission of many warriors of light is to help transform some of the darkness locked in the earth due to all kinds of painful experiences that have happened in the past and are still happening in the world - wars, murders, rapes, robberies, etc. You are not a loser, but an Angel alchemist who illuminates and transforms the darkness. In addition, after each inner rain, the inner garden always blooms even more brightly (maybe it is a reward for the transformation and helping the earth), trust the process and love yourself.
And finally, here is a mini-recommendation for various practices and therapies: When there is that light, when you want to do something, then from my experience, it can contribute to the purification of the body, thoughts and emotions: Spiritual courses, Bach flowers, Kambo, Intestinal cleansing, fasting/ juicing/raw food/alkaline diet, acupuncture, creativity, physical exercises (Yoga, Qigong, etc.).
[Edit: 2022-07-31 I would add the Blue and Red lotuses to those that support plants in such states]