Well, BA, I have a couple of things to say:
1. It seems unlikely to me that she doesn’t want to break up for you. Take her at her word. Is she upset and concerned? Sure, pretty certainly. But I highly doubt you’re able to read her mind.
That said I think you owe it to each other to have a heart-to-heart talk. You love her and it sounds like she very much loves you. Ask her sincerely what’s coming up for her these days. Listen, and ask more questions. Let her know that you’ve really heard her. She’ll love you even more. Don’t try to “fix” or “repair” her or her emotions. Just let her get them out into the open.
2. I personally know how the guilt and shame adds up to feeling like you’re better off gone. That would so terribly hurt her and I know you don’t want that so what do you do?
After listening to her (see #1 above) ask if she’ll listen to you. I’ll bet she will. Pour your heart out to her. Your shame, doubts, worries. Tell her how sad you are, that you feel miserable for hurting her. Go ahead and cry if you need to.
You both have each other and need each other. There’re no guarantees but it sounds to me like you both love each other deeply and are terrified about “what might happen.”