He woke up to darkness. He couldn't even see his hand an inch from his face, so he must have been blinded. That and his killer headache must be the side effects of the bomb. He wondered if it was permanent.
Scientific analysis done, his emotions came rushing back, and with them the grim certainty that the entire Earth was doomed. He'd seen it once, and now it was going to happen again. He had failed to save his planet, the same way he had failed to save Sha're, failed even to save Skaara who was right there and yet still out of reach. He was a failure, and soon he would be too dead to care, but in the meantime he had more than enough time to feel guilty.
He should never have made the stargate work. If he had left it alone, maybe they wouldn't have figured it out. Ra would never have been destroyed, or Apophis attacked, so there would have been no reason for a Goa'uld attack on Earth. He could have been off somewhere digging up artifacts in some remote part of a planet that wasn't in imminent danger of being destroyed.
He knew this kind of thinking was pointless. He had figured out the stargate, and there was no taking that back. But everything was pointless, his whole life was pointless if it had only led to the destruction of his planet and all its people. No one would even care that he had existed except a couple of Goa'uld hosts and the people of a desert planet that would probably be destroyed itself sooner or later.
He was stubborn. He didn't like to give up on things. But he had tried so hard and probably only made things worse. It would be better to do nothing and let the universe destroy itself without his help. And even if he wanted to do something, what could he do, blind and most likely locked up and under guard? It was over, and that was all there was to it.