Obviously the sweater wasn't shrunken, but it simply wasn't stretched enough and apparently it was up to simple physics to solve my gangly girl problem:
First I soaked the sweater in a large tupperware storage container for a few minutes. I sprinkled baking soda in the water because I read something about wool having fabric bonds that can be broken down with salt or something like that I don't even know really, baking soda is just really awesome for treating clothes in general.
...as the water was dripping out I gently tugged at the fabric (mostly the arms) to elongate the shape. The sleeves went from about .5 inches below the bottom hem to about 4 inches below the elongated bottom hem. I let the weight of the water do the rest as instructed.
...because the hanger stretched the shoulders out I was left with these weird points above the seam so I basically wet that entire area after it dried and laid it flat over a towel (that's the proper way to wash a wool sweater if you want to keep its shape). The little points disappeared as the area dried and shrunk back down.
...the final product. As you all can see the sleeves are where they're supposed to be...
Also notice how much better it looks when I styled it in basically the same look I originally wore it in (I did actually wear this look out, I'm not that kind of fashion blogger):
This post was for all the tall ladies out there: you don't have to suffer in silence, just give it a stretch and keep it moving.