I stay in the now. I stop worrying about what has happened in the past. I stop projecting what might happen in the future. I focus on exactly what I need to do to get through the hour. I give myself permission to feel bad.
It's only temporary and this too shall pass are key quotes that run through my mind during the tough times.
(((hugs)))
PS... if you think it's really serious chronic depression, please be brave enough to see a doctor.