Aslam Malaikum Brothers and Sisters,
I also suffered from same evil thoughts when this kind of thoughts coming in your mind keep calm and relaxed.Just observe those thoughts.Tell to yourself i will not and never think about such kind of thoughts.The better way is doing meditation it will help you to make awareness when you become aware such thoughts wont popup this is most affective way.In Meditation keep telling to yourself i wont and never will have such thoughts this all are foolish things. Moreover Pray to ALLAH the one who is the reall protector and ask dua in each and every prayer but dont forget you also have to put your efforts then ALLAH will reward you and also remove this evil thoughts.