Thank you for contacting Positive Personal Growth.
You must be feeling pretty horrible at the moment, thinking that you are no good at anything at all.
Every day, and in every situation, you have a choice. You can choose to be no good at anything at all, and believing this about yourself, not bother to attempt things. Or, you can decide that this time things are going to be different, that you are going to change the way you feel and how you think about yourself, and start to believe that you can do these things.
No one can make these choices but you. No one can force you to do anything you don't want to. If you truly don't enjoy sports, not because you think you aren't any good at them, but because you prefer to do other things, then do other things. Decide what you know in your heart you want to do and do it! Become good and what you enjoy doing.
However if you wished you did play sports, but don't because you think you won't be any good, then change your thinking to "I can do this" and give it a go. It doesn't matter if you fail the first time. Pick yourself up and try again. You will gain the respect of others when you don't give up.
You say all your friends are having fun while you sit and almost cry. You are choosing to sit and almost cry, you have to make the effort to join in with your friends. They can't decide for you that you are going to play, you have to decide this for yourself and join in with them.
I know it's not nice having a low self esteem, I was like that when I was younger, so I understand how you feel. Now I am older (much older!) I realize that I have free will, and freedom of choice. I also know that when I think negative thoughts I get negative results, and this is your situation.
I want you to realize that you are the result of your negative thoughts, that when you have positive thoughts you will get positive results!
I also want to impress firmly into your mind, that no matter what others think of you (or you believe they think) you already are a unique, special, and worthwhile person. You have to believe this, and when you do, your life will change for the better.
Stay strong and change those limiting beliefs that hold you back!