Task: Categorize the tweet's emotional expression, classifying it as either 'neutral or no emotion' or as one or more of the specified emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust) that reflect the tweeter's state of mind.
Tweet: I'm also upset at my incorrect use of a comma. #grammar #struggle #hesitation #backtoschool 🎒📚
This tweet contains emotions: 
anger, disgust, pessimism, sadness