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: Heart heavy for lost furry family members. Remembering Max and Ozzie. Forever friends as 🐶😇
This tweet contains emotions: 
sadness