In the direct aftermath of disappointment, it's important that you experience your emotions. When dealing with anything difficult in life, it's vital to acknowledge your emotional reaction even if it's painful or difficult.  Even your emotions are unpleasant in the wake of disappointment, it's important to let yourself feel them. Your emotional reaction is an important tool when it comes to processing and coping with disappointment. Emotions offer insight into what the event meant to you.  Your emotions may be negative at first. You may be angry, sad, frustrated, and feel discouraged. Allow yourself to experience these emotions fully but remind yourself they are temporary. Try not to analyze your thoughts. Just let them come on their own and silently acknowledge them in your head. It can help to name the thoughts as they come. For example, think to yourself, "Right now, I'm feeling angry. Right now, I'm feeling scared." It's unnatural to expect yourself to bounce back from a disappointment instantly. You need time to take time to mourn what could have been in order to process the disappointment.  It's normal to feel regret following disappointment. There will be an uncomfortable gap between how you wanted things to turn out and reality. It's important you acknowledge this gap.  Try writing down your feelings in a journal. Many people going through setbacks, like breakups or job loss, find they recover from negative feelings quicker when they confront them directly in writing. Take 5 to 10 minutes to just free write your feelings.  Your feelings and thoughts may not necessarily be rational when mourning. You might see things in a very black and white terms. Keep in mind, when confronting your feelings, that they are not an objective analysis of the situation. While it's okay to feel what you're feeling, remind yourself that your emotional response does not define you as a person. Many people have a tendency to be hard on themselves when dealing with disappointment. It's important to be kind to yourself after...

TL;DR in Indonesian:
Rasakan emosi Anda. Berikan waktu untuk berduka. Bersikap baiklah kepada diri sendiri. Ungkapkan.