Help a girl out?

So I'm a senior in high school and I'm really struggling with several things. I know I will be an adult in under a year and I have horrible nightmares, fear of abandonment, difficulty with confrontation, overreacting, etc. It's so hard for me to act like a "grown-up" when I can't even handle simple tasks. I've looked up my symptoms and it pulled up borderline personality disorder but I want to check with a doctor and get help before I'm on my own. Any other ideas what could be going on with me?