What does it mean when you get stabbed in your dream?

The dream expresses feelings of being attacked or injured in some way in real life. Dreams communicate through exaggerated symbols. So being "stabbed" can be a metaphor reflecting a "cutting remark" or some other perceived injury.

A bit more:

Unless a dream is a recurring dream, it most likely means absolutely nothing in particular. However, if it is a recurring dream, then it could mean you feel threatened in some way, such as your job, marriage, health, etc., whether subconsciously or on a conscious level.

Dreams tend to be a way for our minds to "file away" things, events, thoughts, emotions, etc., and really have no specific meaning if it's not a recurring dream.

Maybe it's your intuition telling you have a bad friends that will hurt you or that he or she might "stab you in the back."