The world is the reflection of yourself; you create the world you attract. The way people treat you, is the reflection of what you are, and what you are, is how they treat you.
If you are insecure in your relationship, you are the one who is insecure in that relationship, not your partner; your partner is the reflection of your insecurity.
If you are insecure at your work place, you are the one who is insecure, not your work mates; your insecurity of your work mates is reflection of your insecurity.
If you are insecure of your own business, people will be insecure of your own business too. Business is an idea, and you think that business in your own mind, so, if you are insecure with your business idea, so is the world too.
You are the reflection of how people treat you, and how they see you. Your attitude and actions are what make other people think about you the way they think about you. Your thoughts are what makes other people think of you the way they think of you, in short, other people don’t think of you, you make them think of you through your own thoughts, attitude and actions. And if you have thoughts of confidence in yourself, others will reflect the same confidence to you; but if your thoughts are of insecurity, others will reflect the same insecurity to you.
As said, if you are insecure, guess what? The rest of the world is, too. Do not overestimate the competition and underestimate yourself. You are better than you think.