I'm afraid you might be out of luck here.
I won't claim to know all the odds and ends of weird events in 10 years of SE history, but I very much doubt there's a way for you to get that reputation back. There's two problems to this. The moderators and/or SE employees have absolutely nothing but your word to prove that it was actually your roommate that did this rather than you just changing your mind. We might want to not insinuate you lying, but we can't really trust you blindly either, I'm afraid. You might not know, but it's quite often a "roommate", "brother" or a "coworker" that does the things people get suspended for. ;-)
But even if that was really the case, it's ultimately irrelevant since it would still hinge upon your own responsibility to give your roommate access to your account, willingly or not.
And in addition to that, it would also be a little unfair to rob the users who got these bounties of their awards now. Granted, we rob people of rep all the livelong day when they answer questions that get closed and deleted. Still, the bounties seemed legit (when bounties of such high amounts are given away, we tend to check it's not something shady and the answers that got rewarded seemed largely reasonable).
So on the bottom line, you might have to live with that unlucky incident. I hope you still can bring the motivation to continue SEing, though. Judging from your contributions, it might not take you that long to get your reputation up to par again.