@thisnamechanger - this is happening to me right now. A few years ago I took a year out to work on my mental health and basically try anything and everything I could to get well. I haven't 'cured' the depression (which is lifelong) but I am much much more in control of it as a result of all those investigations. Here's what I do:
1.) Take supplements - B, D spray, iron, tyrosine. Take any that you know boost your metabolism and mood.
2.) Follow the mantra: 'you don't have to want to, you just have to do it' over absolute basics like showering, cleaning teeth and getting dressed each day.
3.) Scale back commitments. Cancel anything you don't have to do. I remind myself this is a physical illness. A majr organ of the body, the brain, ismalfunctioning and i do need that extra rest and less pressure until it is working better.
4.) A walk in nature. I don't manage this every day but do most days. Hill or woodland or park walk.
5.)Eat better. If nothing else, lay off the sugar. Sugar is an evil mood swinger. Refined carbs are too. Minimise sugar and white flour as soon as you start feeling low, and increase food like walnuts, brazils, almonds, turkey (if not veggie/vegan). Also cook with as many anti-inflammatories as you can: garlic, ginger, turmeric, sage. I genuinely notice this difference.
6.) Choose upbeat influences: play lively music, watch comic sketches and feelgood films, read gorgeous poetry and escapist novels, meet up with kind friends who are gentle and don't bitch or whinge about life.
7.) keep a gratitude journal. Just write down three things every evening that you enjoyed that day or are grateful for in your life.
And, best cure of all -
8) Do something you have never done before every single day. Can be tiny: new soap scent, new radio station, new latte flavour. Bit more adventurous: new route to work or school, new outfit, new recipe, new cafe. Can be bolder: apply for new job, sign up for new course, talk to a new person who could become a friend. Can be a bucket-list style thing: visit somewhere you've always wanted to go, do somehting you;ve always intended to try.
Of all my depression cures, this is by far the most effective. It's not perfect. I can find myself thinking: can you only be happy if you are endlessly distracted by going to gigs, theatre, galleries? etc, as a lot of my 'new' stuff does revolve around being entertained rather than me getting off my arse and doing something worthwhile. But it is better than sitting at home moping and sleeping and weeping. So I try not to be too hard on myself when I'm in that stage of recovery.