No, you must never keep your sadness inside you. Express yourself out. Let people know that you are unhappy. Let them know that you are feeling isolated and depressed. Surely, you will feel a lot better and positive.
Satirically, sometimes it may be the situation wherein people in front of whom you want to look happy could be the ones who are responsible for your sadness. Yes, there are situations when the reason for your desolation are the individuals who pretend to be yours; could be anyone from your family or friends. As a result, it becomes extremely tough to flood out your feelings towards them. Eventually, what you do is retain your painful emotions inside and hurt yourself even more.
Remember, in any case; it is never advisable to preserve the sentiments inside you. Summon into your mind that it is even more important to express your true feelings towards those people, in particular. They are ones whom you talk to or meet them daily. You cannot escape from them. Keeping your emotions inside can ruin your life completely. Let the feelings flow out.
However, sometimes it is only your misconceptions about a person which is responsible for your sadness. Shockingly, the person whom you are holding accountable for your sadness doesn’t even know about it. Don’t you feel that the individual concerned must know about it? Yes, you owe him/her at least that much.
Sometimes, you might feel that your expressiveness might lose that person; Rest assured, you will find yourself.