The phrase ‘Head over Heels’ is used when one is very much in love with someone. It is often preceded by the word fall or fell to describe the feelings that typically occur at the beginning of a relationship.
Example of Use: “I have been head over heels about my girlfriend since the day I met her.”
Interestingly, the terms 'head' and 'heels' have been used in English alliterative phrases since the 13th century when the phrase 'heels over head' was common. The term was also used in classical Latin: Per caput pedesque ire. The origin of the idiom 'head over heels' is believed to have its roots in the mid-19th century, when Davy Crockett wrote “I soon found myself head over heels in love with this girl” in 1834.