Inside I'm crying

I laugh when you joke with me,
But inside I am crying.

             I smile when that is what you need to see,
             But inside I am dying.

When you fall down I hold out a hand,
But inside I fell.

            When you are drowning I pull you to land,
            But I am not swimming so well.

I put on a mask that shields the true me,
But I guess you're too busy to see.