Hello, I'd like to help you with your problem.
It sounds like this girl is being very protective of herself, due to being hurt in the past. But it also seems like you are doing the same. You mentioned that you messed up because you were scared you would break up over nothing or that she did not like you. She also seems to pull away when anything about your behavior scares her. With the both of you being afraid of getting hurt, you each had defenses up and took the first opportunity to move away from the relationship in order to protect yourselves.
You did not mention if you talked about how you feltl with your girlfriend, but it's not too late. The one thing that does stand out in your relationship is that neither of you talked about your fears with each other. She did mention that she is afraid to let others in, but when she did feel scared by your behavior, she pulled away instead of talking to you. And you did not talk to her when you feared she did not like you. Communication is vital in any relationship to clear up misunderstandings and to connect with each other when someone, or both of you, feels hurt.
At this point, the two of you seem to be circling each other in a way. She knows you still have feelings for her and she is in your life enough to know the people around you. And you still have feelings for her, which she is aware of. You also mentioned that you are friends. What you might want to do is to talk to her and explain what you are feeling. Be kind and especially gentle with her. Tell her that you have fears yourself of being hurt and that you tend to push someone way when you are afraid. Tell her again that you are sorry about what happened between you. Then try making a connection with her again. Start slowly by asking her to go out for coffee during the day. Make attempts to spend time with her but very casually, as friends. Tread lightly with her, keeping the conversation on the surface for now but let her know she can ask you anything- then be honest with her when she does. As you relax with each other, try asking her for a date. As you move through this time, try to be open with her. You may risk being hurt, but you are hurt now, so weigh the risk with being alone and hurt rather than with her and possibly either being hurt, or having a great relationship.
If she won't see you for coffee or consider going out at all, try to keep your friendship going within the bounds she sets. She may be too scared now of getting hurt. The point is to build trust with her any way you can, even if that is in an office around co workers. Let her see you as being honest and caring. Your behavior will tell her all she needs to know, without even talking to each other.
I hope this helps you,
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