The thoughts more or less remain the same, and it's their effect on me that keeps varying.
I feel similarly. Like this morning I woke up feeling a little anxious and blue for no reason. I thought about my life and there is nothing different to make me feel differently today, but there are just these uncomfortable feelings there. I noticed that I tried to create a story around why I am feeling this way (which is my way to justify the way I am feeling, so I feel more comfortable with the feelings) but then noticed that I can just let the feelings be there and also feel the calm underneath them, too. I can let the feelings that want to be there be and just be calm anyway. Now the feelings softened and I realize I am really tired and feeling overwhelmed with what there is to do this week, and that I have been putting pressure on myself to do too much (which backfires and I procrastinate).
So this is weird how the feelings are important, but I have to stop myself from putting a story on top of them to justify why they might be that way. Then I can relax while feeling the feelings, and they let me know what they are about. I don't have to guess and make a story about why they might be there, I can relax and let them tell me what they are trying to say (and it's often in a small, quiet voice that only comes out when I relax with them.) That is a large part of what seeing a long-term therapist is supposed to be about, so I figure I am saving lots of money just learning to be comfortable with my own feelings enough that they reveal themselves to me.