Your subconscious mind isn’t unlike the friend who just wants to complain and not take any of your advice. In fact, it’s exactly like that friend. So how you deal with it should be the same.
Clearly, you can’t just divorce it and move to another state. I mean you can try, but it will likely stalk any way. Kinda like that ex you can’t get rid of.
Instead you need to practice compassion and empathy. And strengthen your boundaries.
When you feel that mood coming on, say, “hey, I hear you, but we aren’t going to focus on that” then find 3 positives.
Keep that “friend” in check, and don’t let it rain on your parade. It will take time, but it will come around.
I like to think the severity in mood shows how far I’ve actually come from my lowest. I used to live in that place. So instead of getting down that it’s a set back, see it for the mood it is, feed it a healthy breakfast and give it a pep talk.