Perhaps there's something wrong with your code. However, that snippet isn't enough to show what you've done wrong. Please post a complete sketch that demonstrates the problem. If your sketch includes a lot of code not relevant to the problem I suggest you create a minimal sketch that demonstrates the problem in the simplest way you can think of. Quite often, just creating that will enable you to solve the problem for yourself. Even if it doesn't, you've still reduced the amount of code we need to wade through to understand your problem.