I feel something similar to this with my chronic anxiety. My mind twists things so hard that I can't always separate my anxious thoughts from reality. The "what if"s start feeling real even if they are still just "scenarios." My issue doesn't go as deep nor as sad as depression does. The little bit I experienced with being bipolar showed me how much easier anxiety is to handle. Mental illness is exhausting. I can't imagine how tiring chronic depression is.