I've gone through this too and yes it can be very frustrating. Try keeping them in a very quiet area in complete darkness. It seems to help calm them down. Mice can be EXTREMELY nervous and some will eat their babies at the slightest provocation. If all else fails, feed everything off and start over with fresh stock from a different source. Some lines of mice are much better at reproducing then others. Look around to see if you can find someone breeding Swiss Webster mice, the seem to do pretty well typically.