I got bummed recently, so I did a couple of stash-buster projects that each didn't take more than a day or so (the hat took two days, but hey, I had to frog it, so whatever). Sometimes, doing a small project that you can finish really helps to motivate you to work on a bigger project.
Some suggestions: preemie hats/blankets to donate to the Compassionate KAL or your local hospital, baby socks to donate to the local hospital or women's shelter, blanket squares for Warm Up America or a similar project, washcloths, soap covers, towels, headbands, wrist warmers, stuff like that.
And to re-size your sweater? Try just using smaller needles. Although I've never had the problem of a pattern being too BIG for me....