You need to go get professional help before your thoughts become reality. Psychotherapy and medication help alot. Also, try to speak to your parents-their are there for you-take that step-you got to get rid of this before it gets to you first.
I am no doctor, but it sounds very similar to my OCD. I have unwanted thoughts too and in no way do I have a desire to actually do the things it's just a tremendous fear of me being afraid I will do those things. It's like the worst possible thing I can think of and then I am afraid that is what I will do. I have to see a doctor and am on meds and it really helps me.
I also have terrifying thoughts/fears that I would kill the people I love. I am still stuggling with this but therapy and meds really help. I do NOT think these fears will ever become a reality. There is alot of help out there for this. I would suggest seeing a professional.