Task: Analyze the tweet's emotional connotations and classify 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 best portray the tweeter's mental state.
Tweet: I feel ghastly and I'm really hoping it's just a post-birthday slump. Back to full research mode tomorrow either way.
This tweet contains emotions: 
anticipation, disgust, fear, optimism, sadness