Feelings are mental experiences of body states, which arise as the brain interprets emotions, themselves physical states arising from the body’s responses to external stimuli. (The order of such events is: I am threatened, experience fear, and feel horror.)
In other words, an emotion is a physiological experience (or state of awareness) that gives us information about the world, and our feelings are our conscious awareness of the emotion itself. Our feelings then are mental portrayals of what is going on in our bodies when we have an emotion. Feelings are the byproduct of our brains perceiving and assigning meaning to the emotion. Feelings are the next thing that happens after having an emotion, involve cognitive input, usually subconscious, and cannot be measured precisely.
So, it is important for us to remember that individual emotions are temporary, but the feelings they evoke may persist and grow. This happens because the feelings triggered by emotions are not isolated to that particular emotional stimulus, as they are influenced by thoughts, memories, and images that have become subconsciously linked with that particular emotion for you.
Keep in mind, that it works the other way around as well. Feelings can be triggered by emotions and colored by thoughts, but simply thinking about something threatening can also trigger an emotional fear response. Unfortunately, this can set in motion a cycle of painful and confusing emotions which produce negative feelings, which cause more negative emotions.