I'm having thoughts of harming people and harming starngers

it was a month ago, that this started I was watching the new Excorist show and I watched it the whole day pretty much and so I finished watching it and about hour later I get hungry. I went to the kitchen to get an orange because it was late at night like 2 am, so i took the knife to my room because I didn't want to get in trouble but as walking to the hall way with  an orange in one and knife the other. So I notice that the my parents room was locked but because it's rarely locked. So I look at then I get this image of me stabbing my mom comes and this feeling i Get when I know it's dangerous but something inside of you dares. I got really scared because that feeling is only when I jump off dangerous things or when I want to do a backflip. So I was scared, so at the times I was like it would go away soon, it never did it lasted a week so I ended up telling my parents because I couldn't take it anymore. The next day it got worst, I got feelings and urges, that day hurting random people and I went to the hospital talked and they gave me pills to take.since then It got better , I have my ups and downs but it's better than the first day but I still have my moments when those urges come and go, sometimes it's most of the days. I just fear too that I will be that guy one day who kills someone and whatever weird or different  feeling I get worried because of scared of "what if it's the start of me being a murderer" my emotions are all over the place because of this, but never ill do anything of any kind of killings because I've always been good person why stop now I'm a good person. I know I love my parents, family and other people. I'm working hard to overcome this. I'm going to therapy, eating better, and now sleeping better. but recently  I got scared because I turned on STARZ and one of the stupid Saw movies were on, I was seeing someone getting torchered and I wanted to smile. So I'm just scared of ever becoming a murderer. by the way I stayed away of horror movies and many other things that have to do with killing. Thanks guys this is a great platform