I was asked to write this one, and it’s taken a little research. The first question you should ask yourself, and yes, this may be the biggest question, is, “Have you been scratched or bitten by a large creature recently?” If not, there’s almost no chance you’re becoming a frightening puppy.
If you answered “yes” to the first question, inquire as to your habits around the full moon. Ask others, since you may have blacked out during that time. If your brother saw you turn into a gangly wolf and eat someone, then yes, you are a werewolf. If not, ask if you have a pattern of disappearing around the full moon or getting uncharacteristically irate.
This leads to the third issue. In both Twilight and Being Human, is feeling a little “wolfie.” Is it harder to control your temper? Are you more inclined to follow your baser instincts? You could just be going through puberty or need anger management classes, but don’t forget to add “becoming a werewolf” to the possibilities.
If you follow Twilight, one key seems to be body temperature. Do people keep telling you that you have a fever? Has anyone been burned by your touch recently? Both should signal concern.
The fifth alarm bell in werewolfery is appetite. Have you been a vegetarian for years, but suddenly need a bloody steak? Maybe you’re just low on iron, maybe not.
If you do find you’re a werewolf, get help, seriously.
This is my assessment, dear readers. Come on, let me know what I’ve missed. I am humble in my limited knowledge.