If you submitted a K23, you are likely on a path where this won't be the last grant you submit. In other words, get used to this feeling😉
Your score might go up, your score might go down, your score might stay the same. I just had a friend who messaged me about a recent application that went from almost fundable to not discussed because it got assigned a new reviewer who very clearly misread something and tanked it. I've had grants that looked great on resubmission, I easily addressed all reviewer concerns and then it went back to new reviewers on resubmission. I've had questionable grants that I know had significant methodological flaws get fabulous scores and funded on the first submission. I've only been at this a few years and already feel like I've seen just about every possible scenario.
Have a contingency plan. The system is very clearly broken at the level of the individual investigator - I think system-wide we're still probably funding more good science than bad science, but I think its as much luck as anything else when it comes to individual applications as long as you are producing something passable. I think everyone knows it at this point, but its just not easy to fix overnight. Keep submitting applications and be prepared for anything.
I don't think Edison applied for many NIH grants, but his 1% inspiration/99% perspiration quotation was quite prescient.
