At first, I would appreciate it if you opened up and stood up for yourself. Nothing is bad in this and you won’t need to be ashamed off because it really takes courage to show your flaws in front of others. Now the point is that your girlfriend is making fun of all those things you said to her, but this simply gives you the red flag that she doesn’t care or she is not at all concerned about your feelings. The person who digs a pit besides knowing that this can harm you if you fell in that, sorry to say that person is not for you. You should start respecting your feelings and emotions and start avoiding revealing everything in front of her. This will help you to be more confident and stable in your mind, this will help you to clam down when you feel anxious. Things won’t change suddenly the process will be very slow but the ultimate goal will be achieved shortly if you will be stagnant and consistent.