Dearest,
It is not your fault you are the kind of person who has waited for ‘the one’ all your life. It was not your fault that you prayed for half your life for that ‘one’. It wasn't your fault when you witnessed a sickly dying face in your dream and weeks later surprised to see her in real life. No. None of these is your fault. it just happened. You are simply a human being, meant to desire the opposite gender, orchestrated by nature. Just to further the human race. You poor thing got trapped in the universe's big scheme of things.
So, now that you know you are not to blame for falling for that person, now that you know that ‘that person’ found her happiness in another person (recently), what do you do now? You focus on the other things you used to love—trying to put melancholy in words. Characters that you ignored and kept hidden in notes because you convinced yourself you were not worthy to come up with good stories. Not worthy enough to make the readers feel anything. Let me tell you about one thing. Coming up with good ideas has nothing to do with worth. That's bullshit. It's much more to do with your urge to explore. Bringing that urgency is hard when you are busy exploring the outside world. Crafting is an inward thing. You need to follow the character that you feel drawn to, explore, and not overthink how it will end.
Speaking of the end, Bishad, you need to focus on that 'end'. Whenever and/or however that ‘end’ comes we leave it to destiny and think we must about it. Does that mean you ignore your present? Does that mean you don't appreciate the company of people around you? That's a big, bold NO.
Live. (and let live)
Go wherever life takes you. Welcome, every fortune and misfortune alike. Whether you like it or not, you are a human being. It's a fact. Deal with it. You will experience all the things humans are meant to experience. It was written even before the universe was created.
That also includes love. This you have to ignore. Yes, you will fail in this endeavor again and again and again. Throughout your life, you will keep falling for that one girl as if Earth only has one woman. When you do, remind yourself you are an insect. It is unnatural for an insect to fall for a human being. It's a stupid experiment, I know. But if stupidity can keep you from love then why not?
If none of this argument seems convincing, then know this: she will always love men who aren't you.