How could she not apologize, though? Just from all the drama of Mystic Falls in general, on top of him trying to find his place in Lawrence and her having a breakdown because she didn't process things like a normal person? Who did that to people they cared about?! And that was really where the issue was. Elena didn't think she had the right to break down, especially to those she cared about and didn't want to add to their own issues that she just buried it until this happened. But Matt was right. Even if he didn't think she had anything to apologize for, Elena felt it all and felt like she had everything to apologize for.
How quickly Lawrence had turned from a relatively safe from the drama place regardless of the apocalypse to the constant barrage of pain and drama. In a way it made sense, and it had been why Anakin had worried when Rose had gotten injured, when she had made herself sick off caffeine because she was so determined to stay up. He had recognized the falling into those old habits and she had promised she'd be fine because she hadn't anticipated everything else.
Allowing herself to be led back to the couch, Elena just curled up against Matt, finally letting herself appear how she felt. Tired. She was so emotionally drained. The avoiding. The guilt. The constant reminders. The uncertainty. The seeing things and avoiding what she saw because it was too upsetting to truly consider. She had grown so used to having to be strong for others. And she had started it again because she knew that people were worried who had been around before and she wanted to prove she was fine that the mask just went back up. Even if she got short in her answers. Even if she had grown defensive from so many years now between home and Lawrence of her reasons being questioned, doubted.
Struggling to get her breathing back under control, Elena just remained curled up against Matt, clutching his shirt absently. The world had come out from under her all over again and she was drowning again. She had been for a while, she just finally was seeing it again.