But what are you doing in the gym? Isn't it just to get better? So if you only care about other people's bodies, then the meaning of your coming to the gym doesn't exist?
When you see that someone else's figure is better than yours and his movements are more standard than yours, then you should take him as your own goal and try to do that. If you don't work hard, you just envy him and then fall into inferiority. This is a vicious circle.
So don't always feel sorry for yourself on many things. Now that you have found a problem, you should solve it, but you know that your actions can't meet other people's standards, so you should try to make yourself more standard and catch up with others.
If you don't create self-confidence, you are too inferior. Who can help you? No matter who you are, you have your own advantages, so you must find a way to do better than others, and then do better.
If you don't do as well as others, you should try to do as well as others.
Don't be too timid. Since you are determined to change yourself, you must make up your mind. Don't feel depressed and discouraged because of a little thing.
As long as you have perseverance, every effort you make will be rewarded. You should have enough confidence in yourself and work hard towards this belief, so that you can achieve a better and more fulfilling yourself than you are now.