Whatever you may be feeling internally is simply passing through at this moment.
Breathe in and breathe out.
Your feeling state does not make you personally right, wrong, weak, strong, good or bad. Feeling states and thoughts float through us all day long. We are in a constant state of change. Nothing is permanent and nothing lasts forever. Thoughts, feelings, and even our basic biology is constantly in a state of change. Cells are changing every single minute. Some say we get cancer many times a day through flub-ups in cell DNA replication, but this does not always become a diagnosis of "cancer" per say, because we are constantly in a state of repair, replication and change. And the same is true for thought and feelings. They come and they go. Nothing is permanent. They float in and they float out.
It is only when something stops the stream, the flow, that things get out of whack. With thoughts, when we identify with the content of a thought, we get into trouble. For example, pretend the thought: "I can't do this" floats by. If I notice this thought for what it is: just a thought, then I can release it and the thought is free to continue floating by, and another thought will float through and so on and so on. However, if I get "hooked" or identify with the thought content by saying, "yes!, that is me, I can't do this... and...actually... in the past I could not do those other things...", then the spiral begins. The mind has gotten stuck in this content, hooked into the thought and a spiral has begun. This is one way depression or despair begins (which is anger turned inward)....through faulty thought identification.
To stop this spiral from happening you can pull out the hook. You can practice releasing thoughts. They are not really yours anyway. They are simply thoughts and feeling states. They come and they go. Getting hooked means identifying with or conversely fighting a thought or feeling (trying to push it down, deny it, or anesthetize). Either way, through identification or avoidance, you have engaged the thought/feeling state. It will usually stick around until you cut bait or gently release it. Try the fisherman's practice of Catch and Release.
Also note, there is usually a quality of rigidity and self-judgment to this downward spiraling. Add compassion and flexibility, to catch and release and see what happens.
A word on compassion from Pema Chodron:
We cultivate compassion to soften our hearts and also to
become more honest and forgiving about when and how we shut down. Without justifying or condemning ourselves, we do the courageous work of opening to suffering. This can be the pain that comes when we put up barriers or the pain of opening our heart to our own sorrow or that of another being. We learn as much about doing this from our failures as we do from our successes. In cultivating compassion we draw from the wholeness of our experience -- our suffering, our empathy, as well as our cruelty and terror. It has to be this way. Compassion is not a relationship between the healer and the wounded. It's a relationship between equals. Only when we know our own darkness well can we be present with the darkness of others. Compassion becomes real when we recognize our shared humanity ~ Pema Chodron
Resource: Get out of your mind and into your life by Steven Hayes, PhD.