Most children feel like this sometimes; and some feel this way most of the time. They really believe most people do not like them. These feelings and ideas develop in children out of low self-esteem, bad life-experiences, poor social skills, and a life with way too much stress. Focus on your having a positive relationship with your child, understanding this helps a lot by itself. This truth not withstanding, you can do more to help your child with his relationship problems.
Start by believing him. You might say, "Okay, most people don't like you. I'm not one of those who doesn't like you; but most people are. If it's true, it must have something to do with how you act, how you look, or how you treat them. You must be turning them off. If you can figure out how you're doing that, you also can figure out how you can stop doing that. It's hard for me to see how you turn most everyone off. That may be because I love you; but here's a place for you to start. How do you know they don't like you? That'll be a place for you to begin thinking about what you might do about the problem."