Okay, by the standards I use, I'm not certain enough to say for sure, which is why I just did it literal as possible. The best I can guess is that the "地に伏せ" part has to do with this saying:>仰いで天に愧じず、俯して地に怍じず
Which I believe translates to something like "Not feeling shame when looking up to the heavens, not feeling shame when turning down to the ground." and (very broadly) means "if you have a clear conscious, you'll never feel shame."
"地に伏せ" doesn't have the negation though, so it would be more like "feeling shame when looking to the ground". By context I don't think it's too far of a stretch to connect it all to All Might's thoughts on his metaphorical fall from grace, but I don't know that there's enough to confidently guess what Stain might have been leading into before he was cut off. That's about as much as I can offer by way of clarification right now unfortunately.