Ripped out the hem of my grey sweater (for the 4th time) and added a couple of inches. still hated it, so i dropped a bunch of stitches and picked them up again with my trusty crochet hook, so the sweater is now ribbed from the bust to the bottom. it fits a whole bunch better. Still ginormous, but not tent-like.
Discovered the problem. I read the pattern and then cast on for it while I was not looking at it. I remembered the gauge as 16 stitches/4 inches but it's actually written to be 17. So my already-intended-to-be-roomy sweater became a whole bunch roomier.
Whatever. It's fine now. Cozy, comfy, and not an embarrassment.