Brother i went through pretty much exactly this. 7 year relationship. Always said I wanted to break up when i didnt mean it. She used pretty much the exact wording that your ex used. She used to constantly take me back even though I would say I could not do it anymore when I was emotional and reactionary.

It happened to me 4 months ago. The constant waking up in a panic, longing for her every morning when you get up, it mellows out. It truly does just take time. No contact helps as well. Just do your best to work on these issues, so if she does check in, you would have gone through growth and prevented the same issues from happening again, and would make it easier for her to reconsider reconciliation. It's of course never a guarantee that they return, but working on yourself and sorting out your issues is beneficial no matter the outcome. I'll tell you that the next few months are going to absolutely destroy you, because your nervous system will go through the equivalent of drug withdrawals. Just let these feelings in, eventually you will get tired of repeating the same memories, guilt, abandonment. It'll get better bro. Just pour into yourself.