There are negative indices that will solve the problem for you
Depends on how negative the count, and what the situation is.
If you want, you can learn all of the negative count indices for split and double down. They won't increase your win rate or advantage very much, but they will help reduce swings slightly and add some variation to your play that might make you look like a sub- Basic Strategy player. For plays like DD 11 vs. 6, the count has to be very, very, very low to make it not profitable to double because the odds are so heavily in your favor. But BS plays like DD 9 vs. 3 and DD 10 vs. 9, and a few of the split plays have negative indices rather close to zero so they might be worth learning if you are fine tuning your game (i.e., after you have mastered the more important parts of your game) Learning all of the surrender indices also have the effect of lessening your swings slightly.
If your spread is big enough, it won't bother you so much to put out an extra unit on a low count when BS calls for it. Save your fear and loathing for splitting and doubling your big bets! (But you still have to do it!)