Sudden anxiety affecting my feelings

When I'm not anxious, I love my girlfriend and feel a connection to her. When I am anxious, I doubt my feelings all the time, consider breaking up (which wouldnt make any difference on how I feel about anxiety). Anxiety sometimes comes suddenly or after a certain thought, and when it comes, it's hard to make it go away. Most of the time during a whole day I am anxious. What's wrong? I want medical help, cant wait for my meeting with a psychologist. I am afraid he won't understand what I feel and won't "take me seriously" and then it's just wasted money. I'm 17 years old, male btw.