Sorry, but I can't and I won't feel bad for Stefan.
While the act of giving in to save his brother was noble and beautiful, etc, I can’t feel that much for Stefan, because if you really analyze it, he brought this on himself. Like every vampire we seen on the show, he should have learned how to control himself. He was a ticking bomb by choice. He’s only paying the consequences of his irresponsibility. If he wasn’t so proud, if he didn’t interpret the world as black and white, he’d been building a resistance long ago. Sure, he’d make a few victims, but much fewer than now. Klaus only took advantage of a weakness that shouldn’t be there.