You did what you could. Don't torture yourself. He's had you so restrained, what else   could   you have done? You found ways to escape. You saw Harry and the Weasleys one last time and gave them all the information you could. You saved Neville's life. If you hadn't, there wouldn't be a growing rebellion now. There's still hope, small though it might be. There was only so much you could do, considering what you were facing within these walls.