is this recently started or you have always felt it
It happens sometimes. It’s okay.
Try to spend some time with yourself and figure what is it that you are looking from any relationship.
Hey. Sometimes it is better to not think what Is the reason but just live life and make the best of it. Try to calm down your mind and try to focus on how to make it less stresfull. You are never alone, but it is hard to be in peace. Talk about your feelings with friends and family and ask them for advice. And try with meditation, the important is to be happy with you inner self. Good luck
Being lonely in a crowd is the sign that you are lost. You need to find yourself. It's a breakthrough. A beginning of a period where you find yourself. Think what you are good at and your flaws but you love them anyway. Your purpose of living is embedded deep within you and only you have the power of discovering it. Discover your likes your dislikes your morals how do you want to contribute in the society. Find your calling. You'll feel a renewed sense. And it will make you feel like this world needs you and can't do without your presence. Be epic, it's your decision.