[Mifsnavassy]

Recite manzil daily, once a week is "not" sufficient.
Try to memorize kursi and recite when any ill thoughts come.

Finally. Realize that we are humans and far from perfect, no man/woman can say they have never had bad thoughts come upon them.

Ps. Mind what you read or watch, if you constantly read up dark or evil topics it's natural for our brain to constantly think of them and even have dreams of the darkness.

Inshallah all will be well
May Allah give you guidance and protect you from any evil