Every decision you make, the way you talk, the way you move, the way you dress, what you eat - other people are observing you.
One person may think positively, and another may not. That's not always in your control, and many times they'll never tell you what they are truly thinking. Other people's actions will speak louder than their words - that's how you can tell. It's not always fair, but it's just a fact of life. You'll only blow steam trying to change things - You are who you are - Let it be.
Some people will always see you one way. Others may see the potential within you. If someone's perspective of you, is limiting your ability to move upwards or forwards, this may be sign you need to be around (or work for) someone else.
Ultimately, what other people think about you does not matter. What matters is how you see yourself, and what you know you are capable of. Don’t wait for other people’s validation. Prove Them Wrong - Just DO it!