First of all ,God will never leave you to your sin. I know this, because I have had the exact same problem and seeing your post immediately reminded me of my own issues. Try talking to your priest or counselor as often as you can, and never forget that God loves you, and His love is not something you earn, it is love that can never be broken. Believe me, when it comes to the bad habit of pornography and lust, I have been there done that. While you may feel hopeless, doomed, and unsavable by God, you are not! Go to confession whenever possible, go to mass and receive communion when it’s appropriate, and always seek help from others, even when it feels uncomfortable and embarrassing to share your problem.
I’m recovering from my addiction, and I am on the right path, I know you are too, because you are speaking out about it, which takes courage.
God Bless You! My prayers are with you!