General anxiety is more diffuse in nature, doesnt have to have a clear cut cause for appearing and commonly appears in the morning, when having to face the day ahead.
How to release feelings/emotions? They are subtle objects, appearing to you, awareness. If a thought is causing them, then using a reverse thought can help, but you'd have to believe the new thought as much as you did the initial thought.
If you don't know the cause, then it may be something thats buried in your subconscious mind. This is where therapy can help dig into what's really going on in your mind. Once the disturbance is seen and understood, for what it is and worked through, then the feeling of dread will be released.
Take what you like and leave the rest.