Invite the emotions of grief to clean it out of you, and repair your brain. You can explain all of this to people important to you, and ask for support when you explore the old emotions. You don’t have to be alone when feeling miserable. You get to learn that the isolation and alienation and separation are not real now. They are just “memory.”
At the end of the “bad day” you can appreciate that you have walked through one more remembering of childhood pains. You survived. Today you have a full life. Now it is even more full.