💡 Detailed Explanation
「〜あまり」 is used to express that because a feeling or state is so extreme, an unusual or negative result occurs. It emphasizes the nuance of 'as a result of being too nervous.' Other choices: 「せいで」 simply indicates a negative cause/reason. 「ものだから」 is often used with the nuance of making an excuse. 「おかげで」 indicates the cause of a positive result.