Feeling Numb

I think I've never got to this state before. Feeling Numb. Deprived of any feeling, indifferent to all. People ask me how I feel about many things and the answer I give is 'I don't know'. How can I just not know? It is like I lost interest in everything. Anything that happen will cause me no harm, but it will cause me no happiness also. I am just neutral.