Giddiness
Feeling jumpy
Breathlessness
Rapid heartbeat
Lightheadedness
Constant daydreaming
Smiling inappropriately
Butterflies in the stomach
Feverish but in a nice way
Extreme feelings of euphoria
A springlike rise in one's temperature
Hearing singing when there's no one there
An unexpected interest in romantic poetry and schmaltzy love songs
And
Finally
A sudden urge to dance

DIAGNOSIS: You're not sick -
                         You're just in love!