Massive sympathy to you OP.
Here are a few things that help me, although I'm not at all trying to minimize your feelings...
Go for a walk every day, regardless of weather, how I feel, etc. I vary my walks and listen to bbc sounds or audio books. Recently I've been listening to a radio 4 extra version of a Poirot story, and the audio book of Game of Thrones. Sometimes I walk around residential streets and sometimes I head out of my village to footpaths around fields.
Have a routine. I work part-time (teacher) but my days off are structured otherwise I start to feel low. For example I do house work, cooking and baking in the morning, go for a walk after lunch, then watch a film or drama on TV and do some knitting or embroidery. I plan what I'm going to watch, not just aimlessly channel flick.
I'm learning a language on duolingo. I log on every day and it's something different to think about.
I meditate every day using the Calm app. I love it.
I phone my parents regularly, and keep in contact with other family and friends via email, text, etc.
I used to meet a friend for coffee once a week but I'm in tier 3 and not allowed to meet anyone. Also hospitality venues are only allowed to open for meals so that will have to stop.
Keep on top of things like wearing clothes I like, putting on a bit of make up, keeping the house clean, eating healthy food etc. It's very easy for me to just wear pyjamas and eat cheese on toast and chocolate, but I know I will end up feeling worse.
Try to remember that this is a temporary blip.