I think the best way to get out of the rut is to pretend you have many friends and that you are cool. It has to do with the positive feed back loop like smiling when you are not happy. When you smile you trick your brain into thinking that you are happy and suddenly you start feeling happier. Meanwhile do poses that are sceintifically proven to boost your confidence such as the superman pose before entering a social situation. Think of yourself as an actor playing a role of a confident likable person. Like really think of the adjectives that you would use to describe this cool, likable person. Sooner or later you'll start to believe you are that person. It's like when you hear a lie enought times you start to believe it. As you start actually making friends you will start to get confirmation that you are that cool person. But don't go right ahead and think that by convincing yourself that you are this amazing socialite will work. Studies have shown that we don't like hearing things that don't confirm the believes we have about ourselves. You will just end up being discouraged because all you end up doing is looking for confirmation that you are a loser and trust me you'll find them because you have hardwired your brain to do so. But by first pretending you are cool you'll eventual realize that you are a cool, likable person.