Self-defeating thoughts,I have to discuss those with my therapist all the time.
I went down for about a week in dec.,stayed in bed or on the couch and thought what a waste of breath I was.Wouldn't answer the phone,no computer.
I try to think of it as being sucked down into an undertow,if you fight you drown,but if you just let go you will pop back up eventually,all though it may seem like an eternity.
I always think "I should have done this or shouldn't have done that",then it starts to ball up in my mind.Doc said don't even use that word or you will" should" all over yourself.
Be kind to yourself.
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I am the dust that dances in the light. - Rumi