It doesn't sound like people don't like you! It sounds like you've had lots of friends throughout the course of your life. I believe you
are a very likable and lovable person,

.
Relationships change. All the time. And quickly, too! So many factors contribute to the life or death of a friendship and most of the mare truly not personal.
She could, perhaps be at a completely different stage in her life than you are. It doesn't mean she's better than you. Or you better than her. Things are just different.
Sometimes, you just grow out of people.
Don't stress about this. Another friend will come along. The thing is, they will probably leave, too. Lifelong friends are hard to get and it has nothing to do with you being worthy of it. Life just gets int he way,