Determine the emotional tone of the following tweet: "I feel ghastly and I'm really hoping it's just a post-birthday slump. Back to full research mode tomorrow either way.". Use the provided emotions: anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust. Respond with the emotions you identify or "neutral or no emotion".
anticipation, disgust, fear, optimism, sadness