Where Do I Start?

Background; I have a bestfriend who I have been friends with since middle school. We have always been very inseparable. However, a lot of things changed as we were getting older. 

Our 11th grade year: it was an incident where there was a huge misunderstanding about what she was doing for her birthday (She never invited me or told me what she was doing and none of our other bestfriends showed up either), and was very upset that I didn't show up for her birthday to the point where she decided to fully ignore me for a week and make our other friends ignore me as well to the point where they were scared to talk to me unless she wasn't around and then she finally decided to tell me what I did wrong a week later.

Fast-forward to when we are about to go to college, we decided to room together. The first day was very hectic and overstimulating for me. It was fine until it wasn't. I wanted to get used to not being home and actually wanted to spend the first night with just me and her comforting each other and getting to know our roommates. As the night go on, we got into a discussion and the discussion led to us both being in our feelings. She got upset and left the room and decided to leave me with our roommates that we barely know to go be laid up with a boy that she had just met a month before. It got to the point where our roommates noticed and started comforting me. ( Thank God, they were actually sweethearts!) She comes back into the room in the middle of the night and the next morning, I told her that I was going home. The first night told me how everything was going to be and I didn't want that for myself (I still ended up getting my degrees, but from somewhere else.).  My other roommates understood, but she didn't. We stopped talking to each other, until almost a year lately.

Current: Now we are older and I feel myself still struggling with our friendship. I genuinely would love if our friendship could go back to how it was before all of this happened. I miss how our friendship was before I noticed that certain things were wrong. I am very distant now and I go long periods of time without talking to her. When I do reach out, I can tell that she feels a way about my distance, because when I give her an update message about my life, she often dismisses me and state things like "it's not point of texting if we are not going to see each other". I completely understand.

I can fully admit that the distance is because I do be busy, but also, I realized that when we do see each other it be awkward. I still have this fear of if I let her back in, if she would leave and go no contact again like she did when I told her I was going home. She does not know that I have this fear. I don't think she quite understands my distance either. I do not like the idea of letting people have access to me and then just leaving to make me feel like I wasted my time.