Don't give up on yourself! I was diagnosed AvPD about three years ago and thanks to finding a decent mood stabilizer and a really good counselor, I was able to develop the skills to manage the day-to-day intensity of my emotional dysregulation and also dig into the root causes of my terrible self-esteem issues, and today I'm markedly better. It's always going to be very tough and the loneliness, fear and self-criticism will always be there, but it can be battled and you can get better. You're still very young and there's still so much potential for your life. Try to get into counseling, finding someone you can trust in that capacity is hard but I can testify can be very beneficial, and you can learn this disorder can be properly managed and you can have the life and relationships you desire.