I struggle from intrusive and impure thoughts. I believe it is getting better but they still pop up and torture me. But this situation has me worried I committed a mortal sin. I was waking up and I had an impure thought, I do not know what it was about I completely forgot. I ended up getting aroused, and when I realized this I stopped the thought. I know some people say when you wake up you are not in complete control of your thoughts, which could explain why I did not recognize or stop the thought right away until I realized I was aroused. Anyways is this a mortal sin? Thank you.