I think that it's awesome that you voted for Obama even though you may now regret that decisions. I audited his class at UC.
It's hard to regret voting for Obama in 2008 when the other choice was McCain. I can't see myself voting for McCain even with all I know now. Romney was a different story. I feel similar now having to have held my nose and cast a vote for Trump. But there was just no way I would have voted for Clinton. Had the democrats put Sanders forth, I'd have voted for him.