Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: This tweet is dedicated to my back pain, which I do not understand because I am youthful and spry. Full of life. Vivacious.
This tweet contains emotions: 
joy, optimism, sadness