When feeling a really intense emotion, how can I look objectively at myself to see what a normal experience with this emotion should be?

Know that whatever emotion you feel is valid, because it's felt within your own storehouse of emotional experiences and it's unique to you. However, sometimes these emotions can make us feel like we can't function and feel overwhelming. Understanding the root cause often helps. Meditation, reading about what you are going through and seeking the help of an empathetic individual might help you go through this. Hope this helps !