How can a 16-year-old Muslim boy stop porn/masturbation addiction from loving a girl?

Assalamu Alaykum Warahmatullahi Wabarakatuh, I am a 16 year old Arab Muslim boy in the UK (following the Shaf'i madhab) who is concerned about his pornography and masturbation addiction (which for your information, my parents don't know about as I fear that this will cause them disappointment and I don't want them to know about my battle against porn). This battle has been going on for two years and I believe that this rooted from my love for this (hopefully) Christian girl in school (I say hopefully because I never spoke to her for the sake of God, but also because she dresses modestly and doesn't speak to other boys); Knowing that I can't speak to her, I feel overwhelmed by what to do, leaving me always tired and unable to focus on my exams (it is exams seasons as I'm typing this), and leading me to inevitably resort to going home and committing the horrible sin of pornography and masturbation to fulfill my empty sexual desires from knowing I cannot speak to her because that is haram as well. It is constantly getting worse as I know I won't see her again after the exams, making my condition worse and worse every day. This breaks me physically, psychologically and spiritually and I want to get rid of it. I have tried everything from sinecere repentance prayers, distractions, sleeping the desire to masturbate/watch porn away, looked for porn quitting techniques and routines online, and none of that worked. Therefore, I feel like the only thing that will actually get rid of all the porn/masturbation addictions is if I knew a way to get with that girl the halal way, but I don't know when and how to do that, which is why I am here seeking guidance on what to do from this point onwards in life. Jazaakumullahu Khayral Jazaa', Wassalamu Alaykum Warahmatullahi Wabarakatuh.