I can't let it go but I don't know why

It will be hard but not impossible. I have been struggling with this addiction as well but now after only a month I can really tell the difference.

It's good that you have taken some actions against possible triggers, that's a good start Than I would suggest you keep up with the things you real enjoy in life to get yourself as distracted and busy as possible. The reason why you most likely don't feel enjoyment or focus for your real hobbies or interests in life right now is because of your addiction, your brain has become addicted to dopamine and dopamine is a pleasure hormone and since both watching porn and masturbate until orgasm releases much dopamine it will make your natural dopamine levels go crazy if you use/do it to often.

But if you stop watching porn/masturbate and instead doing the real things you enjoy in life, your brain will slowly begin to forget the porn/masturbation and instead begin to enjoy the things you enjoy instead and your dopamine levels will begin to go back to normal again.

Sorry to hear that your relationship with that girl didn't worked out. But I'm sure that you will be able to get in another relationship soon enough and hopefully without your addiction this time.

Remember, this NoFap journey is not a piece of cake, your brain will really put you to the test because all it wants is the dopamine and will go over corpses more or less to achieve it. The most important thing is to have a strong will and dedication that you should not be your brains slave. You should be able to control over your life and how you wanna live it.