It's beautiful and equally puzzling the way the human mind works. We experience situations that make us feel all kinds of way—happy, sad, excited, angry, bewildered, empty, fulfilled, apathetic—and then we make a choice on how we want to react. Most of the times, you just can't help the feelings you have about an event or the way someone treats you. Feeling and experiencing emotions is what makes us human…you experience initial feelings to everything in life and then you make the final decision to act a certain way. This is why no one can ever tell you your feelings are not valid—they are the initial emotions you feel about a situation.
After you allow yourself to experience and process your feelings, you then have an important choice to make: taking action. If you're at a concert where the music makes you feel happy, do you decide to dance around or do you hold back and sit? You likely will get up and dance with the crowd to accentuate the glorious emotions your body and spirit feel. If you walk into a surprise party in your home and feel startled, you then choose how you want to react. After your heart stops racing and you process all of your loving friends in the room, you will likely join in on the fun and revel in the fact that so many people care about you. The wonderful thing about happy, positive feelings is that it's usually easy to choose how to react to them—you do what will make you enhance the cheerful emotions.
It is much more difficult to choose how to react to negative feelings like sadness. You have to take more time to process the emotions and make a final decision to act in a way that may cause further emotional distress to yourself or to others. For example, if one of your best friends excludes you from an invite, you will likely feel hurt and dejected. You can't control the way that you feel about this situation, as it is a universal, initial emotional response to being snubbed by someone you care a lot about. What is important is knowing that you are in full control of how you react and not in how you feel. With this kind of situation, you can decide to express how you feel to your friend or put on a happy face despite the pain you feel inside. Expressing how you feel to someone important to you is the ultimate sign of a true, real friendship, so you should always choose the first option.
Experiencing emotions is such a remarkable aspect of our human nature. It is a truly wonderful thing that we are able to feel such a wide spectrum of feelings stemming from all kinds of events. Never let anyone tell you how to feel or that you are not supposed to experience certain emotions about a situation. These feelings are what makes us the unique and beautiful individuals that we are. In life, some feelings will be harder to process and understand than others, but, ultimately, know that you are always in control of how you react to them.