I do this all the time, although I fight against it with every fibre of my being. I think criticising our own work is somewhat natural for creative people. It is both a curse and a blessing, because while we find ourselves almost constantly swimming in our own negativity, we also always seek improvement.
My approach to this sudden uncertainty about my work is just to say, "I finished a page. It's imperfect, but it's done for now. I'll fix it for printing later." I pretty much always have at least one "problem" panel per page, but I know that if I sit there staring on it for long enough, my urge to change it will never go away. So I take notes on things I can reasonably fix, or things I can do better next time, every time I finish a page, and I move on until I have enough time to go back and fix things.
The urge to constantly redraw pages is incredibly strong and powerful, but we must persevere! Otherwise, we'll never get anywhere.
But, yeah, you are definitely not alone. My satisfaction with my pages usually only lasts like two minutes, tops.
