There are no two ways about it — you will get bluffed. Especially if you are playing well. The important thing is to react well and to evaluate your play up to the point it happens.
I actually think there are two ways of being bluffed, the invited kind and the uninvited. Let me explain.
I find that I most often get bluffed in a painful way when I have played the hand badly up until that point. That is, I set my range up to be bluffed. Either I've deviated from standard play, or worse, I don't know the standard play in the situation.