If you're a shy, introverted self conscious person these attributes can get in the way of what you want to achieve as a photographer. Photographing in public places and the feeling every one's looking at you can be terribly uncomfortable for many.
I remember when I was learning at night school a guy telling us how uncomfortable he was photographing a Ferrari parked in a street. Not because the owner didn't want him to photograph his car, but because passers by asked him if he was a professional.
You've probably noticed I'm lucky enough not to be shy or worried by what passers by think. I have different demons and fears you may not share, but I completely understand those who are uncomfortable in similar situations.
The issue here is not confidence in your abilities as a photographer, it's confidence in general. Suppose someone did come up to you when you're taking a photo in a public place and ask if you're a pro. What do you think would be their response if you told them the truth? That you're learning and are out practising? It's the underlying fear of speaking to a stranger and feeling you need to explain yourself and justify what you're doing in some way.
The truth is - you dont' have to justify or explain anything. You are someone who's learning photography and are practising taking photos, doing your homework and trying to get some nice pics you're proud of. And that's a great response to any inquiry by the way.
Having a camera, lenses and tripod makes you stand out from the crowd and it's the standing out some of us don't like. But I promise you that unless you are doing something obviously suspicious like photographing strangers kids in the playground, some 'heavy dude' leaving a bar or fighting, sneaking photos of girls on the beach - you are completely safe.
This video is my advice to ask yourself some questions to help you get back to what's real and what is imagined when you feel uncomfortable photographing in public places.