I'm realizing that a large percentage of my bad days start with bad sleep.
I wake up tired. I try to get more sleep, so wake up late and skip my morning ritual of puttering around slowly and planning the day. I'm more irritable, more anxious, and less lucid. I eat more junk food. I skip exercise. I'm on my phone more. I have more restless energy and thoughts. I stay up late and can't sleep. The cycle repeats.
If you are caught in this cycle, your main priority should be to get out of it by getting a good night's rest. Drop everything else that you can and dedicate most of the evening to just that. Put away your phone, exercise go for a walk, have a light dinner, and dim the lights. Have night-time tea, magnesium, or melatonin. Go to bed earlier than usual. If you can't sleep, meditate or listen to relaxing music.