I've never been in love, so I have some trouble relating to these kinds of stories. I actually question if the phenomena truly exists.
I have (though not as bad as this) i will share some of my insight.
"Falling in love" is... Pretty much like it's written. There are many reason and many ways to "fall". Maybe you became close first, maybe you didn't think them as such until they confess, or maybe it's from the first sight.
How ever it is you "fall", you fell like you fell from stairs to the ground all the same. Almost helplessly, you got hit by the flood of brain chemicals purposely created to make you able to tolerate another person in your life and personal space.
You are focusing on that person more than you used to, you want the best for them, and what ever you do slowly prioritizing the goal of getting the both of you together for a long time. And like falling, sometimes it hurts cause it's one sided or they already have someone else, sometimes they aren't what you think they were so the feeling you have fades off or worsen as if you hit something bouncy that propell you further than where you stand before you fell, and sometimes it's the softest and most comfortable feeling you ever had.
But as i said, you fell "almost" helplessly. You could let yourself fall, hold the guard rail to stop the fall, brace yourself so it didn't hurt as much, or choose to jump into it even when you know it gonna hurt more. How you choose to react mid fall will decide how you feel after the fall