Phobia and depression. Please help me.

I have been fooled by my friends about 7 years ago about a ghost which is always with me and they can see it. I first didn't mind but by days passing I became very sadist that I even fear to touch others and if I did touch anyone I would wash my hands many times.i would not get sleep and think in many ways about their words Like wise 7 years passed and by reading some holy books i got covered for some extent but still I am getting same feelings and now a days I use to doubt for each and every things in many ways and I get fear like hell and get tensed. I am getting thought to die believing that I am useful for nothing and danger for this society.I can't face this torture anymore. All friends left me.i am living alone. I hid this with my parents and no one knows and suffering this alone. No one understands me. I don't know whom to say a d who would help me. Please help me.