Hello, Aster! First of all, thank you so very much for the tip. I hugely appreciate it, and it is more helpful than you know.
I'm so sorry it's been a rough few months. This is the truth: those who deserve your love don't disappear without warning and without explanation. Before you can work past this, you need to acknowledge the unfair fact that this person may not be worthy of the breadth and depth of your feelings for them. Sometimes there is a tendency to double down in moments like these - I love them deeply, therefore they must have been worthy, therefore there's something wrong with me, I am somehow at fault here, and if I just...understand better, give them more time, give them my patience, perform correctly, say the right things, do the right things, then they will reappear in my life and confirm their worth.
Another truth: feelings can be wrong sometimes. I'd go so far as to venture that feelings are regularly wrong. There is enormous freedom in understanding that emotions are not infallible, that they can absolutely be given attention and weight and never repressed or pushed aside, but they don't have to be our single guiding light. Sometimes we feel personally victimised when what we're really experiencing is the impersonal injustice of the world; sometimes we can be convinced in our hearts that our friends are angry with us when really they're just tired or busy; sometimes the people we love aren't worthy of the purity of that love. There isn't necessarily a deeper meaning to it. You love because you have a vast capacity for love. You heal when that love is abused or misplaced.
And you navigate this the way you navigate any trauma: by giving yourself time, by being honest with yourself, by turning your attention and your focus elsewhere, and by allowing yourself to grow through this. Sometimes people are fickle or thoughtless. Sometimes they make promises they can't keep. Sometimes we misinterpret their intentions, or the sincerity of their intentions. All of this may be painful, but I promise it is not an injury you can't recover from.
This feeling won't last. Some further advice? Try to distract yourself. Give yourself an outlet for your emotions, and then choose to move your focus elsewhere. Try not to dwell. I know it's not easy, but it will get easier. Everything always does. You're worth much more than this.