[RRBB342]

Hi,
I posted this in the general discussion as well because I didn't read the instructions until after. I apologize for the repeat.
I'm new to the forum, thank you for taking the time to read. I am currently experiencing difficulties in my relationship and it's having a severe impact on me. I feel hopeless and don't know what is wrong with me. Basically I have never been the most open person and have trouble sharing my emotions or aspects of my personality or experience that I see as negative. I see now that this makes it hard for me to fully be close to people even when I really love them. I bottle up my emotions a lot and sometimes will have episodes where I freak out, panic, get very angry and frustrated. Different things can trigger it, like frustration over something not working (like a TV, phone, etc), getting lost, having irritation with customer service, not finding what I am looking for, or something more serious like conflict with my girlfriend. I only let the emotions out when I'm alone and don't let other people see. During these episodes, I will yell, curse, talk to myself, look and act crazy I guess.
Recently my phone was broken and I was picking my girlfriend up. I didn't see her and was waiting for a while. I got really frustrated with the phone and wondering where she was. I was freaking out in the car and she saw me yelling and talking alone. She is now suspicious of me and thinks I was arguing with someone else, which I wasn't. She thinks even if I was alone, my behavior is not acceptable, and I agree. I feel ashamed, alone, and hopeless. What is wrong with me? I'm 34 yo female. I have looked online to find what problem I might have but nothing fits. I am seeing a therapist but I have trouble opening up to her also
I love my girlfriend very much and want to make the relationship work. What steps can I take to restore her trust and heal the relationship? I also want to fix this for myself so I can be a more whole person, not feel ashamed of parts of myself and be in control of my emotions.