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: I don't think I can go to work tomorrow since val has left #GBBO I need a day to mourn
This tweet contains emotions: 
sadness