There are numerous synonyms for the phrase "am fascinated". One of the most common is "am intrigued", meaning to be interested and curious about something. "Am captivated" is another synonym, indicating strong interest and an inability to look away. "Am spellbound" is a more dramatic option, invoking imagery of being fully entranced by something. "Am absorbed" suggests a deep level of interest and focus on the subject at hand. "Am mesmerized" implies a kind of hypnotic fascination, while "am obsessed" indicates a persistent preoccupation. Overall, there are many words to describe the feeling of being fascinated, each with its unique connotations and nuances.