(Let's be clear: "antisocial" means you don't respect the rights of others, and seek to violate social bounds. Seems more like you're suffering from "social anxiety", where you have difficulty interacting with people, or perhaps agoraphobia, which is the fear of large crowds.)

Administrative or office work might be good for you, as you will be around the same faces most of the time. Or you could look around for photo internships to get an early start and a feel for what sort of social circumstances will be involved.

At some point, you're going to have to tackle this problem. Photography as a line of work is just as much about salesmanship as it is about making photos. You have to appease your existing clients, and attract new ones. And depending on what sort of events you cover, you might be shooting in large crowds. So customer service and retail jobs, although they involve being around people, will give you better experience in the long run.

If you're fine around a few people, then you're halfway there. Confidence is key”if you can appear confident, you can seal the deal. That nagging feeling that you need to get away will show through, and your customers will not be as forthcoming.

I had the same problem. In fact I also worked as a cashier at KFC 8 years ago. It sucks. And it isn't just you. Places like KFC and McD's expect you to break your back and sweat blood and tears for them, for very little money and talk to you like you are a piece of sh't if you do the slightest thing wrong. There's nothing wrong with you honestly.

Like the other dude said, the problem is social anxiety. As a general rule, the public in general as customers are complete idiots and will complain and make you feel small over the slightest thing. What you need is routine and working with a group of people you can get used to being around. Maybe night shifts in a warehouse would be ok for you? Doing gardening on a self-improved basis? Designing websites? Try and do something you enjoy and that isnt minimum wage and customer-facing and you'll be. And also try to remember, most people dont like their jobs, but you need to find something you can tolerate otherwise you'll end up a complete bum.