Partial answer (working backwards):
They took from me something near to my heart. I crossed the Atlantic, my short became long, but I was still essentially myself.
Not sure.
I gave up heroin. I introduced my companions to my friend Syrah.
Not sure.
Once accustomed to a life of comfort, I left all ease behind. I had no place to rest, but I was always of two minds—to meander in and around the trees, or to blow through and past them?
Can't figure the first part out yet but the latter part gives "wind".
I chased a husbandman's wife until she attacked me in her usual manner. I left, diminished, but I felt no loss.
Husbandman's wives cut off tails ala 3 blind mice, so taking away 'd' gives "win" (no loss there).
I made a teacher mad, and she tore my head off. This made me one of the popular kids.
Taking off the 'w' gives "in" - being one of the "in crowd" means you're cool (or so they say).
And now I am here before you, nearly unrecognizable—but a fraction of what I once was—but focus your sight just on my head. You'll see I was here all along.
Looking at just the start of "in" gives you - surprise, surprise, "I" which was indeed here all along!