Dressing up as a clown and commiting violent acts against the elderly

When I was 15years old I read Stephen Kings Novel I.T for the for the time, it was compelling and scary to me. After reading the Book, everything seemed different to me, the way I looked at certain things like people getting nervous or children getting scared and even clowns, many months later down the line I begin halluninating about stuff I never thought possible I would, psychologically I knew something wasn't right when I started getting violent for no reason. During my 16 birthday I went out for a meal with my family and friends to a fancy restaurant, after everyone had ordered their food, about 20minutes later the waiters started delivering the food out to us, the waiter carrying my food was this old man who looked fairly stable, but he managed to drop my food on the floor by accident. Ever since my 16th birthday I've fantasised about dressing up as a clown similar from the one in the book I.T, and taking a blunt or rusty object and smashing in the backsides of elderly people until they either bleed to death, or apologise to me. Is this normal or do I need help?