Fluency can be learned. You said yourself that your speech has changed over time. Yes, stuttering has a neurological basis. But it doesn't have to be a disability. I was a severe stutterer from childhood until my mid 20s. Never a fluent sentence. Blocks that would last longer than I had air in my lungs. But with proper speech therapy and hard work, I was able to learn fluency. Most of the people I work with have no idea I was a stutterer. Only those with whom I've shared. School speech therapy is not at all the same as professional speech therapy. As the adage goes "you get what you pay for." No one said your friends are going to leave you. People grow in different directions. School, careers, and relationships take people to new places. If you've only seen one speech therapist, I would seek out a more professional resource.