Does the expression head over heels mean the same as head over feet? To be madly in love with someone?
The phrase is definitely head over heels - to be madly in love with someone typically used to describe a "new love" or "like a new love" condition.
I just met this girl and I'm head over heels in love.
She's lucky! They've been married for 20 years and he's still head over heels in love with her.
head over feet is never used this way. In fact as far as I know head over feet has no special idiomatic meaning and I can't come up with a situation where those three words would come out of my mouth in that order except for when reading this SE question outloud.
(As an aside- this is where Urban Dictionary and the like must be taken with a grain of salt because it does list head over feet to mean the same as head over heels, but no native speaker I know would ever utter it.)