<human>: Could you distill the essence of the text into 1-3 sentences?

I'm 16 and this is my first serious relationship, it's had it's ups and downs but for the most part I've really been enjoying myself. My gf has pretty bad anxiety. It's so bad at times she'll stay up for days when she's stressed about school. (9 days was the longest) She also has low self esteem

We were texting each other and she's in one of those periods due to exams. Bad mood swings and crazy stress, so she just dropped and bomb on me saying and I quote.

"All I keep thinking about is how disappointed you must be and how much you regret asking me out. You probably feel trapped in this relationship you don't want to be in and you won't leave because you think i'll do something like hurt myself. So you just stay."

I then asked how long she'd been thinking these things and she said for the entire duration of our relationship. Extremely upsetting because she's the most wonderful girl I've ever met. I told her that I'm not going to leave and I want to talk about it tomorrow in person, she said "I don't think I'll ever believe that" and "he'll leave and I'll be alone again." keeps replaying in her head.

I'm not going to leave her, but it's scary because it must be torture for her. So I'm wondering if I can do anything, or say something or maybe some advice for her, or me from someone who's been in this situation. 

She's never told me this stuff before so I see it as a cry for help, that or she's going to break up with me because of how she feels I dunno..
<bot>: My girlfriend is scared I'll leave her and she can't stop thinking about it. I'm going to talk with her tomorrow and I'm asking for any advice on what I could say or do